Use Java 11 for build process

Author: swesteme

.github/workflows/ci.yml

@@ -17,10 +17,10 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v2
-      - name: Set up JDK 1.8
+      - name: Set up JDK 11
         uses: actions/setup-java@v1
         with:
-          java-version: 1.8
+          java-version: 11
       - name: Build with Maven
         run: mvn -B -Dgpg.skip verify
       - name: Upload code coverage