chore(package): update @angular-devkit/build-angular to version 0.7.5

Closes #27

Author: greenkeeper[bot]

demo/package.json

@@ -38,7 +38,7 @@
     "zone.js": "^0.8.26"
   },
   "devDependencies": {
-    "@angular-devkit/build-angular": "~0.6.0",
+    "@angular-devkit/build-angular": "~0.7.5",
     "@angular/cli": "^6.1.3",
     "@angular/compiler-cli": "^6.1.2",
     "@angular/language-service": "^6.1.2",