Update JDK version from 17 to 21 for extension publishing. (#858)

Author: rgrunber

.github/workflows/publish-extensions.yml

@@ -48,7 +48,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: "microsoft"
-          java-version: "17"
+          java-version: "21"
       - name: Install dependencies for native modules
         run: |
           sudo apt-get update