GH-4781 update github actions workflow to use java 21

Author: hmottestad

.github/workflows/dash-license.yml

@@ -15,12 +15,12 @@ jobs:
         uses: actions/setup-java@v3
         with:
           distribution: 'temurin'
-          java-version: '20'
+          java-version: '21'
       - name: Cache local Maven repository
         uses: actions/cache@v3
         with:
           path: ~/.m2/repository
-          key: ${{ runner.os }}-jdk20-maven-${{ hashFiles('**/pom.xml') }}
+          key: ${{ runner.os }}-jdk21-maven-${{ hashFiles('**/pom.xml') }}
           restore-keys: |
             ${{ runner.os }}-jdk20-maven-
       - name: Run license-check

.github/workflows/develop-status.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        jdk: [11, 20]
+        jdk: [11, 21]
 
     steps:
     - uses: actions/checkout@v2

.github/workflows/main-status.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        jdk: [11, 20]
+        jdk: [11, 21]
 
     steps:
     - uses: actions/checkout@v2

.github/workflows/pr-verify.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        jdk: [11, 20]
+        jdk: [11, 21]
     steps:
     - uses: actions/checkout@v2
     - name: Set up JDK