Bump postcss from 7.0.38 to 8.2.13

Bumps [postcss](https://github.com/postcss/postcss) from 7.0.38 to 8.2.13.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@7.0.38...8.2.13)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:development
...

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

package.json

@@ -61,7 +61,7 @@
         "eslint-plugin-jest": "^24.3.6",
         "eslint-plugin-prettier": "^3.3.1",
         "eslint-plugin-react": "^7.24.0",
-        "postcss": "^7.0.38",
+        "postcss": "^8.2.13",
         "postcss-cli": "^7.1.1",
         "prettier": "2.2.1",
         "tailwindcss": "npm:@tailwindcss/postcss7-compat@^2.2.16",