chore(fix): should not include "Main" property in package.json (#2549)

* chore(fix): should not include "Main" property in package.json

if we are not using 'Main' property asn entry point it should be removed, it is not a required property

In the case of the codesandbox it is causing the following error

"Error: Could not fetch dependencies, please try again in a couple seconds: Something went wrong while packaging the
dependency @patternfly/patternfly@2.43.1: ENOENT: no such file or directory, scandir '/tmp/960130286/node_modules/@patternfly/patternfly/n'"

* chore(fix): pr comment fix

package name changed back to "@patternfly/patternfly"

package.json

@@ -4,7 +4,6 @@
   "version": "0.0.0-development",
   "keywords": [],
   "license": "MIT",
-  "main": "n/a",
   "scripts": {
     "backstop:approve": "node test/approve-conflicts.js",
     "backstop:init": "node test/create-references.js",