added testing for java 11

Author: ckoegel

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         os: [windows-2016, windows-2019, ubuntu-18.04, ubuntu-20.04]
-        java-version: ['8']
+        java-version: ['8', '11']
     steps:
     - name: Checkout
       uses: actions/checkout@v2