Updating phonegap-plugin-push to v.2.2.3

[FredrikLastow]

• The update was done by removing and then adding the plugin with the PhoneGap CLI
• Removes SENDER_ID variable

  As of version 2.0.0 the SENDER_ID parameter has been removed at install time. Instead, you put your google-services.json (Android) and/or GoogleService-Info.plist in the root folder of your project and then add the following lines into your config.xml. ...

• Thought this would fix the eslint security alert, but the eslint version is the same with v.2.2.3, sadly. Since I already updated it I thought that I might as well make a pr to see if we want the update either way.

[FredrikLastow]

Doesn't seem like this does much good for us, so I'll close it. Not hard to replicate in the future if we ever need to.