build(deps): bump polished from 3.6.6 to 4.0.3 in /docs (#1482)

Bumps [polished](https://github.com/styled-components/polished) from 3.6.6 to 4.0.3.
- [Release notes](https://github.com/styled-components/polished/releases)
- [Commits](styled-components/polished@v3.6.6...v4.0.3)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/package-lock.json

@@ -38,7 +38,7 @@
     "gatsby-transformer-remark": "^2.8.28",
     "gatsby-transformer-sharp": "^2.5.15",
     "gatsby-transformer-yaml": "^2.4.11",
-    "polished": "^3.6.6",
+    "polished": "^4.0.3",
     "prism-react-renderer": "^1.1.1",
     "prop-types": "^15.7.2",
     "puppeteer": "^5.4.1",