Bump the JVM version to 11 in the workflow file:

The error message from the GitHub Actions workflow:
```text
> Could not resolve all files for configuration ':buildSrc:compileClasspath'.
   > Could not resolve com.android.tools.build:gradle:8.5.2.
     Required by:
         project :buildSrc
      > Dependency requires at least JVM runtime version 11. This build uses a Java 8 JVM.
```

Author: ShreckYe

.github/workflows/demo-gh-pages.yml

@@ -31,10 +31,10 @@ jobs:
       - name: Setup Pages
         uses: actions/configure-pages@v5
 
-      - name: Set up JDK 8
+      - name: Set up JDK 11
         uses: actions/setup-java@v4
         with:
-          java-version: "8"
+          java-version: "11"
           distribution: "temurin"
 
       - name: Setup Gradle