Update dependency happypack to v5

Author: renovate-bot

package-lock.json

@@ -99,7 +99,7 @@
     "fork-ts-checker-webpack-plugin": "0.4.1",
     "fs-extra": "5.0.0",
     "git-pre-hooks": "1.2.0",
-    "happypack": "4.0.1",
+    "happypack": "5.0.0",
     "jest": "22.4.3",
     "jest-cli": "22.4.3",
     "jsdom": "11.6.2",