Plugin: Pin pkg to v4.3.8 (#103)

Seems like v4.4.2 of pkg broke the build for Windows.

Author: marefr

package.json

@@ -39,7 +39,7 @@
     "@types/node": "^10.0.9",
     "husky": "^3.1.0",
     "lint-staged": "^9.5.0",
-    "pkg": "^4.4.2",
+    "pkg": "4.3.8",
     "prettier": "^1.19.1",
     "tsc-watch": "^1.0.21",
     "tslint": "^5.20.1",