Bump actions/checkout and actions/setup-java to v4
See https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/
diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 99cb8ca..19cb2dd 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -14,9 +14,9 @@
         dist: [ 'zulu' ]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up JDK ${{ matrix.jdk }}
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@v4
         with:
           java-version: ${{ matrix.jdk }}
           distribution: ${{ matrix.dist }}