build: update @angular to version 9.0.0-next.15

Author: alan-agius4

package.json

@@ -32,8 +32,8 @@
     "webpack": "^4.0.0"
   },
   "devDependencies": {
-    "@angular/compiler": "9.0.0-next.14",
-    "@angular/compiler-cli": "9.0.0-next.14",
+    "@angular/compiler": "9.0.0-next.15",
+    "@angular/compiler-cli": "9.0.0-next.15",
     "typescript": "3.6.4",
     "webpack": "4.41.2"
   }