Update actions/setup-java digest to 3a4f6e1

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/java-ci.yml

@@ -18,7 +18,7 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-maven-
       - name: Set up JDK 21
-        uses: actions/setup-java@7a6d8a8234af8eb26422e24e3006232cccaa061b # v4
+        uses: actions/setup-java@3a4f6e1af504cf6a31855fa899c6aa5355ba6c12 # v4
         with:
           distribution: 'temurin'
           java-version: 21