Bump css-what from 2.1.2 to 2.1.3 in /website (#473)

Bumps [css-what](https://github.com/fb55/css-what) from 2.1.2 to 2.1.3.
- [Release notes](https://github.com/fb55/css-what/releases)
- [Commits](https://github.com/fb55/css-what/compare/v2.1.2...v2.1.3)

---
updated-dependencies:
- dependency-name: css-what
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: James Ramm <JamesRamm@users.noreply.github.com>

website/yarn.lock

@@ -1535,9 +1535,9 @@ css-url-regex@^1.1.0:
   integrity sha1-g4NCMMyfdMRX3lnuvRVD/uuDt+w=
 
 css-what@2.1, css-what@^2.1.2:
-  version "2.1.2"
-  resolved "https://registry.yarnpkg.com/css-what/-/css-what-2.1.2.tgz#c0876d9d0480927d7d4920dcd72af3595649554d"
-  integrity sha512-wan8dMWQ0GUeF7DGEPVjhHemVW/vy6xUYmFzRY8RYqgA0JtXC9rJmbScBjqSu6dg9q0lwPQy6ZAmJVr3PPTvqQ==
+  version "2.1.3"
+  resolved "https://registry.yarnpkg.com/css-what/-/css-what-2.1.3.tgz#a6d7604573365fe74686c3f311c56513d88285f2"
+  integrity sha512-a+EPoD+uZiNfh+5fxw2nO9QwFa6nJe2Or35fGY6Ipw1R3R4AGz1d1TEZrCegvw2YTmZ0jXirGYlzxxpYSHwpEg==
 
 cssnano@^3.10.0:
   version "3.10.0"