build: update webpack to version 4.38.0

Author: renovate-bot

package.json

@@ -36,6 +36,6 @@
     "@angular/compiler": "~8.1.0",
     "@angular/compiler-cli": "~8.1.0",
     "typescript": "3.4.5",
-    "webpack": "4.37.0"
+    "webpack": "4.38.0"
   }
 }