fix: package.json to reduce vulnerabilities (#1512)

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-NODESASS-535499
- https://snyk.io/vuln/SNYK-JS-NODESASS-535501
- https://snyk.io/vuln/SNYK-JS-NODESASS-535503
- https://snyk.io/vuln/SNYK-JS-NODESASS-535504
- https://snyk.io/vuln/SNYK-JS-NODESASS-535505

package.json

@@ -14,7 +14,7 @@
     "grunt-cli": "^1.2.0",
     "grunt-contrib-less": "1.3.0",
     "grunt-less-to-sass": "duvillierA/grunt-less-to-sass#0.0.11",
-    "grunt-sass": "^1.0.0",
+    "grunt-sass": "^2.0.0",
     "jit-grunt": "^0.9.1",
     "node-sass": "^4.11.0"
   },