ci: update upload artifact version to v4

Author: tharropoulos

.github/workflows/lint.yml

@@ -25,7 +25,7 @@ jobs:
         run: redocly bundle openapi.yml --output bundled-openapi.yml
 
       - name: Upload bundled specification
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: bundled-openapi
           path: bundled-openapi.yml