Bump postcss-cli from 6.1.3 to 7.1.0

Bumps [postcss-cli](https://github.com/postcss/postcss-cli) from 6.1.3 to 7.1.0.
- [Release notes](https://github.com/postcss/postcss-cli/releases)
- [Changelog](https://github.com/postcss/postcss-cli/blob/master/CHANGELOG.md)
- [Commits](postcss/postcss-cli@6.1.3...7.1.0)

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

Author: dependabot-preview[bot]

package.json

@@ -47,7 +47,7 @@
     "npm-run-all": "^4.1.5",
     "parcel-plugin-bundle-visualiser": "^1.2.0",
     "percy": "^0.21.0",
-    "postcss-cli": "^6.1.3",
+    "postcss-cli": "^7.1.0",
     "postcss-fontpath": "^1.0.0",
     "posthtml-expressions": "^1.1.1",
     "posthtml-include": "^1.2.0",