chore(deps): update dependency sass-loader to v7

Author: renovate-bot

package-lock.json

@@ -62,7 +62,7 @@
     "node-sass": "^4.9.0",
     "postcss-loader": "^2.0.8",
     "prettier": "1.14.0",
-    "sass-loader": "^6.0.6",
+    "sass-loader": "^7.0.0",
     "semantic-release": "^15.9.3",
     "semantic-release-chrome": "^1.0.1",
     "semantic-release-firefox": "^1.0.4",