Bump actions/upload-artifact from 5 to 6 (#370)

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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build-windows.yml

@@ -41,7 +41,7 @@ jobs:
             Compress-Archive -DestinationPath "${{github.workspace}}\mapcache.zip" -Path "${{github.workspace}}\mapcache.xml", "mapcache.dll", "mapcache.fcgi.exe", "mapcache_seed.exe", "mapcache_detail.exe"
 
         - name: Upload binary artifacts
-          uses: actions/upload-artifact@v5
+          uses: actions/upload-artifact@v6
           with:
             name: binaries
             path: mapcache.zip
@@ -110,7 +110,7 @@ jobs:
             }
 
         - name: Upload test artifacts
-          uses: actions/upload-artifact@v5
+          uses: actions/upload-artifact@v6
           with:
             name: test-results
             path: |