Test against JDK 16

Author: marcphilipp

.github/workflows/main.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: ['6', '8', '11', '15', '17-ea']
+        java: ['6', '8', '11', '16', '17-ea']
     steps:
       - uses: actions/checkout@v2
       - name: Download Maven # Download with default JDK because OpenJDK 6 does not support TLS 1.2