fix(package): update core-js to version 3.6.5

Closes #28

Author: greenkeeper[bot]

package.json

@@ -126,7 +126,7 @@
   "dependencies": {
     "chalk": "^2.3.0",
     "conf": "^1.4.0",
-    "core-js": "^2.5.3",
+    "core-js": "^3.6.5",
     "get-stdin": "^5.0.1",
     "meow": "^4.0.0",
     "ora": "^1.3.0",