Remove version field from package.json

The `version` field is only needed if the package is to be published. For this project, packge.json is only used to
define dependencies. For this reason, having a `version` field is harmful because it increases the effort and complexity
of making a release, and also is likely to get out of sync with the true version.

Author: per1234

package-lock.json

@@ -1,6 +1,5 @@
 {
   "name": "setup-task",
-  "version": "0.0.0",
   "private": true,
   "description": "Setup Task action",
   "main": "lib/main.js",