Added CI pipeline

[gardusig]

Changes

• Github Action on PR events
  • Check code format with dotnet format
  • Related fixes

Resources

• Relevant files are:
  • .github/workflows/pull_request.yml
  • Dockerfile
• As reproduced here, this file added a linter requirement

[gardusig]

Will be continued here: https://github.com/conductor-sdk/conductor-csharp/pull/20