docs: update changelog headers (#1164)

Author: dandhlee

Diff for: CHANGELOG.md

@@ -128,7 +128,7 @@
 * issues/192254729 ([#915](https://www.github.com/googleapis/python-aiplatform/issues/915)) ([0f22ff6](https://www.github.com/googleapis/python-aiplatform/commit/0f22ff61460a3f2bd55d2c10c4ee06e582f03944))
 * use open_in_new_tab in the render method. ([#926](https://www.github.com/googleapis/python-aiplatform/issues/926)) ([04618e0](https://www.github.com/googleapis/python-aiplatform/commit/04618e0563b8588eec2ccd8342c6085ca08b5adb))
 
-### [1.8.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.8.0...v1.8.1) (2021-12-14)
+## [1.8.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.8.0...v1.8.1) (2021-12-14)
 
 
 ### Bug Fixes
@@ -176,7 +176,7 @@
 * Reverted IDs in model_service snippets test ([#871](https://www.github.com/googleapis/python-aiplatform/issues/871)) ([da747b5](https://www.github.com/googleapis/python-aiplatform/commit/da747b5ffca3c12b8d64bc80bfe93da5afde0d43))
 * Update name of BQ source parameter in samples ([#859](https://www.github.com/googleapis/python-aiplatform/issues/859)) ([f11b598](https://www.github.com/googleapis/python-aiplatform/commit/f11b598f9069f77e86631ada53941876aea010bc))
 
-### [1.7.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.7.0...v1.7.1) (2021-11-16)
+## [1.7.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.7.0...v1.7.1) (2021-11-16)
 
 
 ### Features
@@ -215,7 +215,7 @@
 * Fix pydocs README to be consistent with repo README ([#821](https://www.github.com/googleapis/python-aiplatform/issues/821)) ([95dbd60](https://www.github.com/googleapis/python-aiplatform/commit/95dbd6020ee8f3037b0834eb39312b5d7e5fd8e1))
 * Update sample with feedback from b/191251050 ([#818](https://www.github.com/googleapis/python-aiplatform/issues/818)) ([6b2d938](https://www.github.com/googleapis/python-aiplatform/commit/6b2d93834734b6789c13ef3782b1b3632f5c6133))
 
-### [1.6.2](https://www.github.com/googleapis/python-aiplatform/compare/v1.6.1...v1.6.2) (2021-11-01)
+## [1.6.2](https://www.github.com/googleapis/python-aiplatform/compare/v1.6.1...v1.6.2) (2021-11-01)
 
 
 ### Features
@@ -235,7 +235,7 @@
 
 * release 1.6.2 ([#809](https://www.github.com/googleapis/python-aiplatform/issues/809)) ([e50b049](https://www.github.com/googleapis/python-aiplatform/commit/e50b0497574411a9c7462d76dca489281ee48d83))
 
-### [1.6.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.6.0...v1.6.1) (2021-10-25)
+## [1.6.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.6.0...v1.6.1) (2021-10-25)
 
 
 ### Features
@@ -287,7 +287,7 @@
 * **PipelineJob:** use name as output only field ([#719](https://www.github.com/googleapis/python-aiplatform/issues/719)) ([1c84464](https://www.github.com/googleapis/python-aiplatform/commit/1c84464e3130f9db81cd341306b334f9a490587f))
 * use the project id from BQ dataset instead of the default project id ([#717](https://www.github.com/googleapis/python-aiplatform/issues/717)) ([e87a255](https://www.github.com/googleapis/python-aiplatform/commit/e87a255705a5d04ade79f12c706dc842c0228118))
 
-### [1.4.3](https://www.github.com/googleapis/python-aiplatform/compare/v1.4.2...v1.4.3) (2021-09-17)
+## [1.4.3](https://www.github.com/googleapis/python-aiplatform/compare/v1.4.2...v1.4.3) (2021-09-17)
 
 
 ### Features
@@ -305,15 +305,15 @@
 
 * release 1.4.3 ([#715](https://www.github.com/googleapis/python-aiplatform/issues/715)) ([b610486](https://www.github.com/googleapis/python-aiplatform/commit/b6104868161a236fc5585855b5948a5e3294aea2))
 
-### [1.4.2](https://www.github.com/googleapis/python-aiplatform/compare/v1.4.1...v1.4.2) (2021-09-10)
+## [1.4.2](https://www.github.com/googleapis/python-aiplatform/compare/v1.4.1...v1.4.2) (2021-09-10)
 
 
 ### Features
 
 * add explanation metadata `get_metadata_protobuf` for reuse ([#672](https://www.github.com/googleapis/python-aiplatform/issues/672)) ([efb6d18](https://www.github.com/googleapis/python-aiplatform/commit/efb6d18f868086bc53aceab60942eb837ced65b7))
 
 
-### [1.4.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.4.0...v1.4.1) (2021-09-07)
+## [1.4.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.4.0...v1.4.1) (2021-09-07)
 
 
 ### Features
@@ -424,7 +424,7 @@
 * making the uploader depend on tensorflow-proper ([#499](https://www.github.com/googleapis/python-aiplatform/issues/499)) ([b95e040](https://www.github.com/googleapis/python-aiplatform/commit/b95e0406566879e8f71cefda72b41dc6fe4e578f))
 * Set prediction client when listing Endpoints ([#512](https://www.github.com/googleapis/python-aiplatform/issues/512)) ([95639ee](https://www.github.com/googleapis/python-aiplatform/commit/95639ee1c2c9cb66624265383d4d27bed3ff7dbd))
 
-### [1.1.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.1.0...v1.1.1) (2021-06-22)
+## [1.1.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.1.0...v1.1.1) (2021-06-22)
 
 
 ### Features
@@ -488,7 +488,7 @@
 * correct link to fieldmask ([fdc968f](https://www.github.com/googleapis/python-aiplatform/commit/fdc968f49e89a5c7ca14692080c0ae7e8b6e0865))
 * removes tinyurl links ([fdc968f](https://www.github.com/googleapis/python-aiplatform/commit/fdc968f49e89a5c7ca14692080c0ae7e8b6e0865))
 
-### [1.0.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.0.0...v1.0.1) (2021-05-21)
+## [1.0.1](https://www.github.com/googleapis/python-aiplatform/compare/v1.0.0...v1.0.1) (2021-05-21)
 
 
 ### Bug Fixes
@@ -558,7 +558,7 @@
 * env formatiing ([#379](https://www.github.com/googleapis/python-aiplatform/issues/379)) ([6bc4c61](https://www.github.com/googleapis/python-aiplatform/commit/6bc4c612d5471911f82ee5ada9fb3a9307ee836f))
 * remove Optional type hint on deploy ([#345](https://www.github.com/googleapis/python-aiplatform/issues/345)) ([79b0ab1](https://www.github.com/googleapis/python-aiplatform/commit/79b0ab13e6d08a12ac0a0971a8001e9ddb8baf56))
 
-### [0.7.1](https://www.github.com/googleapis/python-aiplatform/compare/v0.7.0...v0.7.1) (2021-04-14)
+## [0.7.1](https://www.github.com/googleapis/python-aiplatform/compare/v0.7.0...v0.7.1) (2021-04-14)
 
 
 ### Bug Fixes
@@ -596,7 +596,7 @@
 
 * skip create data labeling job sample tests ([#254](https://www.github.com/googleapis/python-aiplatform/issues/254)) ([116a29b](https://www.github.com/googleapis/python-aiplatform/commit/116a29b1efcebb15bad14c3c36d3591c09ef10be))
 
-### [0.5.1](https://www.github.com/googleapis/python-aiplatform/compare/v0.5.0...v0.5.1) (2021-03-01)
+## [0.5.1](https://www.github.com/googleapis/python-aiplatform/compare/v0.5.0...v0.5.1) (2021-03-01)
 
 
 ### Bug Fixes
@@ -660,7 +660,7 @@
 
 * update readme ([#81](https://www.github.com/googleapis/python-aiplatform/issues/81)) ([19dc31a](https://www.github.com/googleapis/python-aiplatform/commit/19dc31a7e63ec112e9d0dc72e22db04910137d07))
 
-### [0.3.1](https://www.github.com/googleapis/python-aiplatform/compare/v0.3.0...v0.3.1) (2020-11-13)
+## [0.3.1](https://www.github.com/googleapis/python-aiplatform/compare/v0.3.0...v0.3.1) (2020-11-13)
 
 
 ### Features