Update actions/cache to v4

Author: heuermh

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
         with:
           java-version: '11'
           distribution: 'temurin'
-      - uses: actions/cache@v2
+      - uses: actions/cache@v4
         with:
           path: ~/.m2
           key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}

.github/workflows/deploy.yml

@@ -18,7 +18,7 @@ jobs:
           server-id: sonatype-nexus-snapshots
           server-username: MAVEN_USERNAME
           server-password: MAVEN_PASSWORD
-      - uses: actions/cache@v2
+      - uses: actions/cache@v4
         with:
           path: ~/.m2
           key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}