Test on JDK16

Author: LunNova

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
         runs-on: ubuntu-latest
         strategy:
             matrix:
-                jdk: [11, 15]
+                jdk: [11, 15, 16]
         steps:
             - uses: actions/checkout@v2
             - uses: actions/cache@v2.1.4