chore(package): update copy-webpack-plugin to version 5.0.4

Closes #232

Author: greenkeeper[bot]

package.json

@@ -103,7 +103,7 @@
     "bundlesize": "^0.15.3",
     "codelyzer": "^3.1.2",
     "compression-webpack-plugin": "^1.0.0",
-    "copy-webpack-plugin": "^4.0.1",
+    "copy-webpack-plugin": "^5.0.4",
     "cross-env": "^5.0.1",
     "cross-spawn": "^5.0.1",
     "css-loader": "^0.28.7",