feat: next release from main branch is 3.2.0 (#709)

Author: Neenu1995

.github/release-please.yml

@@ -7,6 +7,10 @@ branches:
     handleGHRelease: true
     releaseType: java-yoshi
     branch: java7
+  - bumpMinorPreMajor: true
+    handleGHRelease: true
+    releaseType: java-backport
+    branch: 3.1.x
 bumpMinorPreMajor: true
 handleGHRelease: true
 releaseType: java-yoshi

.github/sync-repo-settings.yaml

@@ -46,6 +46,20 @@ branchProtectionRules:
       - units (11)
       - 'Kokoro - Test: Integration'
       - cla/google
+  - pattern: 3.1.x
+    isAdminEnforced: true
+    requiredApprovingReviewCount: 1
+    requiresCodeOwnerReviews: true
+    requiresStrictStatusChecks: false
+    requiredStatusCheckContexts:
+      - dependencies (8)
+      - dependencies (11)
+      - lint
+      - clirr
+      - units (8)
+      - units (11)
+      - 'Kokoro - Test: Integration'
+      - cla/google
 permissionRules:
   - team: yoshi-admins
     permission: admin