fix(deps): update dependency postcss-safe-parser to v6 (#136)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Author: renovate[bot]

package-lock.json

@@ -91,7 +91,7 @@
         "eslint-utils": "^3.0.0",
         "lodash": "^4.17.19",
         "postcss": "^8.2.4",
-        "postcss-safe-parser": "^5.0.0",
+        "postcss-safe-parser": "^6.0.0",
         "postcss-scss": "^3.0.0",
         "postcss-selector-parser": "^6.0.2",
         "postcss-styl": "^0.8.0"