Github Actions: Build with Java 11

Author: skalarproduktraum

.github/workflows/build-main.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Set up Java
         uses: actions/setup-java@v3
         with:
-          java-version: '8'
+          java-version: '11'
           distribution: 'zulu'
           cache: 'maven'
       - name: Set up CI environment

.github/workflows/build-pr.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Set up Java
         uses: actions/setup-java@v3
         with:
-          java-version: '8'
+          java-version: '11'
           distribution: 'zulu'
           cache: 'maven'
       - name: Set up CI environment