chore(package): update @angular-devkit/build-angular to version 0.7.4

Closes #44

Author: greenkeeper[bot]

package.json

@@ -48,7 +48,7 @@
     "ts-node": "^3.3.0",
     "tslint": "^5.10.0",
     "typescript": "2.7.2",
-    "@angular-devkit/build-angular": "~0.6.6"
+    "@angular-devkit/build-angular": "~0.7.4"
   },
   "greenkeeper": {
     "ignore": [