Update github actions to v4

Author: dkayiwa

.github/workflows/maven.yml

@@ -22,13 +22,13 @@ jobs:
       JAVA_VERSION: ${{ matrix.java-version }}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Set up JDK
-        uses: actions/setup-java@v1
+        uses: actions/setup-java@v4
         with:
           java-version: ${{ matrix.java-version }}
       - name: Cache local Maven repository
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.m2/repository
           key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}