chore: bump node-sass to 4.13.1

Author: antonreshetov

Diff for: package.json

@@ -54,7 +54,7 @@
     "highlight.js": "^9.12.0",
     "lint-staged": "^8.1.5",
     "marked": "^0.5.1",
-    "node-sass": "^4.9.3",
+    "node-sass": "^4.13.1",
     "sass-loader": "^7.1.0",
     "vue-svg-loader": "^0.10.0",
     "vue-template-compiler": "^2.5.17"