Update engines to use variables

[jcesarmobile]

Platforms affected

Android

What does this PR do?

Update plugin.xml and package.json engines to the ones that allow variables

What testing has been done on this change?

Checklist

• Reported an issue in the JIRA database
• Commit message follows the format: "CB-3232: (android) Fix bug with resolving file paths", where CB-xxxx is the JIRA ID & "android" is the platform affected.
• Added automated test coverage as appropriate for this change.

[jcesarmobile]

@macdonst sorry, I missed this, the variable only works on cordova 7.1.0 and greater.

Do you think we should do a minor bump for this?

[shazron]

I would recommend a minor bump.

[jcesarmobile]

@shazron updated the engine to apply to 4.1.0.
Didn't bump the plugin version yet as I think that is done on the plugin release process.