Add Java version 16 to the test matrix

Author: axel-op

.github/workflows/test.yml

@@ -8,7 +8,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
-        java-version: [8, 11]
+        java-version: [8, 11, 16]
         version: ["1.6", ""]
     runs-on: ${{ matrix.os }}
     steps: