Bump eslint from 7.20.0 to 7.21.0

Bumps [eslint](https://github.com/eslint/eslint) from 7.20.0 to 7.21.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](https://github.com/eslint/eslint/compare/v7.20.0...v7.21.0)

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

package.json

@@ -1,7 +1,7 @@
 {
   "dependencies": {
     "csso-cli": "^3.0.0",
-    "eslint": "^7.13.0",
+    "eslint": "^7.21.0",
     "html-minifier": "^4.0.0",
     "stylelint": "^13.11.0",
     "stylelint-config-standard": "^20.0.0",