Update the cache action to v4

Author: gayaldassanayake

.github/workflows/maven.yml

@@ -21,7 +21,7 @@ jobs:
         java-version: 11.0.16+8
         distribution: 'temurin'
     - name: Cache Maven packages
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         path: ~/.m2
         key: ${{ runner.os }}-m2