Bump @material-ui/lab from 4.0.0-alpha.60 to 4.0.0-alpha.61 in /website

Bumps [@material-ui/lab](https://github.com/mui-org/material-ui/tree/HEAD/packages/material-ui-lab) from 4.0.0-alpha.60 to 4.0.0-alpha.61.
- [Release notes](https://github.com/mui-org/material-ui/releases)
- [Commits](https://github.com/mui-org/material-ui/commits/HEAD/packages/material-ui-lab)

---
updated-dependencies:
- dependency-name: "@material-ui/lab"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

website/package-lock.json

@@ -10,7 +10,7 @@
   "dependencies": {
     "@material-ui/core": "^4.12.3",
     "@material-ui/icons": "^4.11.2",
-    "@material-ui/lab": "^4.0.0-alpha.60",
+    "@material-ui/lab": "^4.0.0-alpha.61",
     "common-tags": "^1.8.2",
     "date-fns": "^2.28.0",
     "google-protobuf": "^4.0.0-rc.1",