Bump actions/upload-artifact from 5 to 6

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...v6)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/gradle.yml

@@ -98,22 +98,22 @@ jobs:
       run: ./gradlew runClientGameTestWithMods --stacktrace --warning-mode=fail
 
     - name: Upload screenshots
-      uses: actions/upload-artifact@v5
+      uses: actions/upload-artifact@v6
       if: ${{ success() || failure() }}
       with:
         name: screenshots
         path: build/run/*/screenshots
         compression-level: 0
 
     - name: Upload logs
-      uses: actions/upload-artifact@v5
+      uses: actions/upload-artifact@v6
       if: ${{ success() || failure() }}
       with:
         name: logs
         path: build/run/*/logs/latest.log
 
     - name: Upload crash reports
-      uses: actions/upload-artifact@v5
+      uses: actions/upload-artifact@v6
       if: ${{ failure() }}
       with:
         name: crash-reports