fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-CROSSSPAWN-8303230

Author: snyk-bot

package.json

@@ -22,7 +22,7 @@
     "grunt-contrib-copy": "0.5.0",
     "grunt-contrib-watch": "0.5.3",
     "grunt-nodemon": "0.4.0",
-    "grunt-sass": "^1.1.0",
+    "grunt-sass": "^3.0.0",
     "grunt-text-replace": "0.3.12",
     "hogan.js": "3.0.2",
     "marked": "^0.3.5",