Add code coverage details

[EugeneKisel-sm]

• readme file was updated to include ci build status and code coverage
• dockerfile was updated to support code coverage
• coverlet.collect library was added to testing project to support code coverage
• pull_request.yml updates:
  • support code coverage
  • add concurrency to cancel old builds if any
  • update checkout from v3 to v4

Preview:

[codecov-commenter]

Welcome to Codecov 🎉

Once you merge this PR into your default branch, you're all set! Codecov will compare coverage reports and display results in all future pull requests.

ℹ️ You can also turn on project coverage checks and project coverage reporting on Pull Request comment

Thanks for integrating Codecov - We've got you covered ☂️

[shaileshpadave]

lgtm