Bump css-what and critical in /website

Bumps [css-what](https://github.com/fb55/css-what) to 2.1.3 and updates ancestor dependency [critical](https://github.com/addyosmani/critical). These dependencies need to be updated together.


Updates `css-what` from 2.1.0 to 2.1.3
- [Release notes](https://github.com/fb55/css-what/releases)
- [Commits](https://github.com/fb55/css-what/compare/v2.1.0...v2.1.3)

Updates `critical` from 1.3.2 to 1.3.10
- [Release notes](https://github.com/addyosmani/critical/releases)
- [Changelog](https://github.com/addyosmani/critical/blob/master/CHANGELOG.md)
- [Commits](https://github.com/addyosmani/critical/compare/v1.3.2...v1.3.10)

---
updated-dependencies:
- dependency-name: css-what
  dependency-type: indirect
- dependency-name: critical
  dependency-type: direct:production
...

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

website/package.json

@@ -1,7 +1,7 @@
 {
   "dependencies": {
     "codemirror": "^5.37.0",
-    "critical": "^1.3.2",
+    "critical": "^1.3.10",
     "gulp": "^3.9.1",
     "gulp-rename": "^1.2.3",
     "html5shiv": "^3.7.3",