fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade: - https://snyk.io/vuln/SNYK-JS-NODESASS-535500

Author: snyk-bot

package.json

@@ -40,7 +40,7 @@
  "fs-extra": "0.30.0",
  "glob": "^7.1.1",
  "json-loader": "0.5.4",
- "node-sass": "3.10.1",
+ "node-sass": "4.11.0",
  "os-name": "2.0.1",
  "postcss": "5.2.0",
  "proxy-middleware": "0.15.0",
@@ -89,7 +89,7 @@
  "ionic-cz-conventional-changelog": "1.0.0",
  "jest": "^18.0.0",
  "mock-fs": "3.11.0",
- "node-sass": "3.10.1",
+ "node-sass": "4.11.0",
  "rewire": "^2.5.2",
  "rimraf": "2.5.4",
  "rxjs": "5.0.0-beta.12",