chore(package): update @angular-devkit/schematics to version 8.0.4

Closes #20

Author: greenkeeper[bot]

demo/package.json

@@ -40,7 +40,7 @@
   },
   "devDependencies": {
     "@angular-devkit/build-angular": "^0.13.9",
-    "@angular-devkit/schematics": "^7.3.9",
+    "@angular-devkit/schematics": "^8.0.4",
     "@angular/cli": "^7.3.9",
     "@angular/compiler-cli": "^7.2.15",
     "@angular/language-service": "^7.2.15",