Test against JDK 22 EA

Author: yrodiere

.github/workflows/build.yml

@@ -152,6 +152,7 @@ jobs:
           # and it's useful to test that.
           - { name: "20", java_version_numeric: 20, from: 'jdk.java.net', jvm_args: '--enable-preview' }
           - { name: "21-ea", java_version_numeric: 21, from: 'jdk.java.net', jvm_args: '--enable-preview' }
+          - { name: "22-ea", java_version_numeric: 22, from: 'jdk.java.net', jvm_args: '--enable-preview' }
     steps:
     - uses: actions/checkout@v2
     - name: Get year/month for cache key