Update actions

Author: alanocallaghan

.github/workflows/gradle.yml

@@ -28,7 +28,7 @@ jobs:
       with:
         arguments: build
     - name: Upload artifacts
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: ${{ github.event.repository.name }}-${{ github.event.pull_request && github.head_ref || github.ref_name }}
         path: build/libs

.github/workflows/release.yml

@@ -13,10 +13,10 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v3
-      - name: Set up JDK 17
+      - name: Set up JDK
         uses: actions/setup-java@v3
         with:
-          java-version: '17'
+          java-version: '21'
           distribution: 'temurin'
       - name: Validate Gradle wrapper
         uses: gradle/wrapper-validation-action@v1