ci: use java version 8

Author: Maximilian Häming

.github/workflows/main.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Setup JDK
         uses: actions/setup-java@v3.13.0
         with:
-          java-version: '11'
+          java-version: '8'
           distribution: 'temurin'
           cache: gradle
       - name: Create local gradle properties files