ci: bump gradle/actions from 3 to 6

Bumps [gradle/actions](https://github.com/gradle/actions) from 3 to 6.
- [Release notes](https://github.com/gradle/actions/releases)
- [Commits](https://github.com/gradle/actions/compare/v3...v6)

---
updated-dependencies:
- dependency-name: gradle/actions
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/build-kiosk.yml

@@ -26,7 +26,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@v3
+        uses: gradle/actions/setup-gradle@v6
         with:
           gradle-version: '8.6'
 

.github/workflows/build-scale-gateway.yml

@@ -29,7 +29,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@v3
+        uses: gradle/actions/setup-gradle@v6
         with:
           gradle-version: '8.4'