Coverage goes JDK 21

Author: sfuhrm

.github/workflows/coverage.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ 11 ]
+        java: [ 21 ]
     steps:
     - uses: actions/checkout@v2
     - name: Set up JDK ${{ matrix.java }}