Update Gradle Wrapper Validation Action to v3

The current version (v1) of Gradle Wrapper Validation Action
is outdated and may stop working in the future.

Let's update the workflow dependency, and
use the format as recommended in
https://github.com/gradle/wrapper-validation-action/blob/main/README.md.

.github/workflows/gradle.yml

@@ -27,7 +27,7 @@ jobs:
         run: ./run-checks.sh
 
       - name: Validate Gradle Wrapper
-        uses: gradle/wrapper-validation-action@v1
+        uses: gradle/actions/wrapper-validation@v3
 
       - name: Setup JDK 17
         uses: actions/setup-java@v1