Add Java 16-ea to GitHub builds.
diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 9f1886f..6686319 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -29,6 +29,8 @@
         include:
           - java: 15-ea
             experimental: true        
+          - java: 16-ea
+            experimental: true
         
     steps:
     - uses: actions/checkout@v1