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

Author: renovate-bot

.github/workflows/buildpack-integration-test.yml

@@ -176,7 +176,7 @@ jobs:
             -output-file=${{ inputs.output-file }} \
             -validate-mapping=false
       - name: 'Upload Artifact'
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         if: always()
         with:
           name: ${{ matrix.type }}_${{ inputs.builder-runtime }}_${{ inputs.builder-url == '' && 'no_builder_url' || 'with_builder_url' }}_buildpack_integ_logs