Bump node-sass from 4.12.0 to 4.13.1

Bumps [node-sass](https://github.com/sass/node-sass) from 4.12.0 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@v4.12.0...v4.13.1)

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

Author: dependabot[bot]

package-lock.json

@@ -23,7 +23,7 @@
     "@angular/router": "^8.2.14",
     "SavjeeCoin": "github:SavjeeTutorials/SavjeeCoin#5cc294c488604546526bf277eceef9ea443b762b",
     "core-js": "^2.6.5",
-    "node-sass": "^4.12.0",
+    "node-sass": "^4.13.1",
     "rxjs": "~6.5.3",
     "zone.js": "^0.9.1"
   },