ci: add gh-actions workflow

[zachawilson]

Platforms affected

• CI: ios & android

Motivation and Context

Add GH Actions to run plugin tests using cordova-paramedic

• Android: https://github.com/SwitchCaseGroup/cordova-plugin-statusbar/actions/runs/1192373245
• iOS: https://github.com/SwitchCaseGroup/cordova-plugin-statusbar/actions/runs/1192373244

Description

Adding two new workflows.

• Trying to follow workflows in existing apache repo ci: add gh-actions workflow cordova-paramedic#215

Testing

Tests can be verified by viewing workflow results

• Android: https://github.com/SwitchCaseGroup/cordova-plugin-statusbar/actions/runs/1192373245
• iOS: https://github.com/SwitchCaseGroup/cordova-plugin-statusbar/actions/runs/1192373244

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary

[zachawilson]

The PR #214 is different in that it is running the linter and then uploading coverage reports using https://github.com/codecov/codecov-action