chore(deps): update actions/upload-artifact action to v6

Author: renovate[bot]

.github/workflows/activation.yml

@@ -11,7 +11,7 @@ jobs:
         uses: game-ci/unity-request-activation-file@v2
 
       - name: Upload artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v6
         with:
           name: ${{ steps.getManualLicenseFile.outputs.filePath }}
           path: ${{ steps.getManualLicenseFile.outputs.filePath }}

.github/workflows/build.yml

@@ -32,7 +32,7 @@ jobs:
           targetPlatform: StandaloneWindows64
 
       - name: Upload build artifacts
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v6
         with:
           name: Build
           path: build