Updated testutils.

Author: kpinnipa

package.json

@@ -78,7 +78,7 @@
     "@babel/preset-env": "^7.12.1",
     "@babel/preset-react": "^7.12.5",
     "@jupyterlab/builder": "^3.0.0-rc.13",
-    "@jupyterlab/testutils": "^3.0.5",
+    "@jupyterlab/testutils": "^3.0.10",
     "@testing-library/react": "^11.1.1",
     "@types/enzyme": "^3.10.8",
     "@types/enzyme-adapter-react-16": "^1.0.6",