fix(package): update @angular/platform-browser to version 5.2.1

Closes #20

Author: greenkeeper[bot]

package.json

@@ -20,7 +20,7 @@
     "@angular/core": "^4.0.0",
     "@angular/forms": "^4.0.0",
     "@angular/http": "^4.0.0",
-    "@angular/platform-browser": "^4.0.0",
+    "@angular/platform-browser": "^5.2.1",
     "@angular/platform-browser-dynamic": "^4.0.0",
     "@angular/router": "^4.0.0",
     "@nglibrary/ngx-choosy": "^1.1.0",