Use JDK 21 explicitly for report publishing

since the publish job does not have a matrix

Author: marko-bekhta

.github/workflows/ci-report.yml

@@ -24,10 +24,10 @@ jobs:
         with:
           persist-credentials: false
           ref: ${{ github.ref }}
-      - name: Set up Java ${{ matrix.os.java.version }}
+      - name: Set up Java 21
         uses: actions/setup-java@v4
         with:
-          java-version: ${{ matrix.os.java.version }}
+          java-version: 21
           distribution: temurin
       # https://github.com/actions/cache/blob/main/examples.md#java---maven
       - name: Cache local Maven repository
@@ -65,4 +65,4 @@ jobs:
           done
           exit $status
         env:
-          DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY_PR }}
+          DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY_PR }}