Update dependencies of the Java CI workflow

The current workflow dependencies are outdated and
may stop working in the future. For instance,
codecov-action@v3 stopped working during AY2324S2
(see nus-cs2103-AY2324S2/forum#729).

Let's update the workflow versions to the latest ones to
minimize the chance of them breaking in future batches.

.github/workflows/gradle.yml

@@ -27,11 +27,12 @@ jobs:
         run: ./run-checks.sh
 
       - name: Validate Gradle Wrapper
-        uses: gradle/wrapper-validation-action@v1
+        uses: gradle/actions/wrapper-validation@v3
 
       - name: Setup JDK 17
-        uses: actions/setup-java@v1
+        uses: actions/setup-java@v4
         with:
+          distribution: 'zulu'
           java-version: '17'
           java-package: jdk+fx
 
@@ -40,6 +41,6 @@ jobs:
 
       - name: Upload coverage reports to Codecov
         if: runner.os == 'Linux'
-        uses: codecov/codecov-action@v3
-        env:
-          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+        uses: codecov/codecov-action@v4
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}