CI: drop JDK 13 and 14, add 15

Author: SethTisue

Diff for: .circleci/config.yml

@@ -7,12 +7,9 @@ executors:
   scala_jdk11_executor:
     docker:
       - image: circleci/openjdk:11-jdk
-  scala_jdk13_executor:
+  scala_jdk15_executor:
     docker:
-      - image: circleci/openjdk:13.0.1-jdk-buster
-  scala_jdk14_executor:
-    docker:
-      - image: circleci/openjdk:14-ea-26-jdk-buster
+      - image: circleci/openjdk:15-buster
 
 commands:
   sbt_cmd:
@@ -105,28 +102,16 @@ workflows:
           java_version: jdk11
           scala_version: 3.0.0-M2
       - scala_job:
-          name: jdk13_2.12
-          java_version: jdk13
-          scala_version: 2.12.12
-      - scala_job:
-          name: jdk13_2.13
-          java_version: jdk13
-          scala_version: 2.13.4
-      - scala_job:
-          name: jdk13_3.0
-          java_version: jdk13
-          scala_version: 3.0.0-M2
-      - scala_job:
-          name: jdk14_2.12
-          java_version: jdk14
+          name: jdk15_2.12
+          java_version: jdk15
           scala_version: 2.12.12
       - scala_job:
-          name: jdk14_2.13
-          java_version: jdk14
+          name: jdk15_2.13
+          java_version: jdk15
           scala_version: 2.13.4
       - scala_job:
-          name: jdk14_3.0
-          java_version: jdk14
+          name: jdk15_3.0
+          java_version: jdk15
           scala_version: 3.0.0-M2
       - scalajs_job:
           name: sjs1.0_2.12

Diff for: .travis.yml

@@ -13,7 +13,7 @@ env:
   - SCALAJS_VERSION=         ADOPTOPENJDK=8
   - SCALAJS_VERSION=1.3.1    ADOPTOPENJDK=8
   - SCALAJS_VERSION=         ADOPTOPENJDK=11
-  - SCALAJS_VERSION=         ADOPTOPENJDK=13
+  - SCALAJS_VERSION=         ADOPTOPENJDK=15
 
 install:
   - git fetch --tags # get all tags for sbt-dynver