build(deps-dev): Bump mini-css-extract-plugin from 1.3.7 to 1.3.9

Bumps [mini-css-extract-plugin](https://github.com/webpack-contrib/mini-css-extract-plugin) from 1.3.7 to 1.3.9.
- [Release notes](https://github.com/webpack-contrib/mini-css-extract-plugin/releases)
- [Changelog](https://github.com/webpack-contrib/mini-css-extract-plugin/blob/master/CHANGELOG.md)
- [Commits](https://github.com/webpack-contrib/mini-css-extract-plugin/compare/v1.3.7...v1.3.9)

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

package.json

@@ -265,7 +265,7 @@
     "jsdom": "^16.4.0",
     "json-loader": "^0.5.7",
     "listr": "^0.14.3",
-    "mini-css-extract-plugin": "^1.3.7",
+    "mini-css-extract-plugin": "^1.3.9",
     "node-loader": "^1.0.2",
     "node-sass": "^5.0.0",
     "prettier": "^2.2.1",

yarn.lock

@@ -8780,10 +8780,10 @@ min-indent@^1.0.0:
   resolved "https://registry.yarnpkg.com/min-indent/-/min-indent-1.0.1.tgz#a63f681673b30571fbe8bc25686ae746eefa9869"
   integrity sha512-I9jwMn07Sy/IwOj3zVkVik2JTvgpaykDZEigL6Rx6N9LbMywwUSMtxET+7lVoDLLd3O3IXwJwvuuns8UB/HeAg==
 
-mini-css-extract-plugin@^1.3.7:
-  version "1.3.7"
-  resolved "https://registry.yarnpkg.com/mini-css-extract-plugin/-/mini-css-extract-plugin-1.3.7.tgz#51848320f736bebccbe9875e38c776c364a4a8eb"
-  integrity sha512-NDyOUqdfKVIfWTludTcZ6JDOMsIdWgyTEECYbfvZszPpkMRyQLvukqtLr92tfukPQxVZNCKb8TkOilFBvS5RIw==
+mini-css-extract-plugin@^1.3.9:
+  version "1.3.9"
+  resolved "https://registry.yarnpkg.com/mini-css-extract-plugin/-/mini-css-extract-plugin-1.3.9.tgz#47a32132b0fd97a119acd530e8421e8f6ab16d5e"
+  integrity sha512-Ac4s+xhVbqlyhXS5J/Vh/QXUz3ycXlCqoCPpg0vdfhsIBH9eg/It/9L1r1XhSCH737M1lqcWnMuWL13zcygn5A==
   dependencies:
     loader-utils "^2.0.0"
     schema-utils "^3.0.0"