Bump node-sass from 4.13.0 to 4.13.1 (#45)

Bumps [node-sass](https://github.com/sass/node-sass) from 4.13.0 to 4.13.1.
- [Release notes](https://github.com/sass/node-sass/releases)
- [Changelog](https://github.com/sass/node-sass/blob/master/CHANGELOG.md)
- [Commits](sass/node-sass@v4.13.0...v4.13.1)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package-lock.json

@@ -70,7 +70,7 @@
     "html-webpack-plugin": "^3.2.0",
     "jest": "^24.9.0",
     "mini-css-extract-plugin": "^0.9.0",
-    "node-sass": "^4.13.0",
+    "node-sass": "^4.13.1",
     "npm-run-all": "^4.1.5",
     "sass-loader": "^8.0.0",
     "script-ext-html-webpack-plugin": "^2.1.4",