Maintenance Updates

[garrytrinder]

Prompted by #11

This issue is to make this action consistent with the action-cli-login and enable us to update dependencies with confidence that we are not breaking existing functionality.

• Add unit tests using mocha
• Add code coverage using c8
• Add test workflow
• Add PR check workflow
• Remove releases from readme
• Update examples to use semver @v2
• Update dependencies
• Update maintainers
• Update tsconfig
• Remove tslint
• Update to use node16
• Update master branch to main
• Update using to node20