Use pydantic alias for serialization of BGP/BFD events

[johannaengland]

Scope and purpose

Fixes #331.

This pull request

• changes the API

Contributor Checklist

Every pull request should have this checklist filled out, no matter how small it is.
More information about contributing to Zino can be found in the
README.

• Added a changelog fragment for towncrier
• Added/amended tests for new/changed code
• Added/changed documentation
• Linted/formatted the code with black, ruff and isort, easiest by using pre-commit
• The first line of the commit message continues the sentence "If applied, this commit will ...", starts with a capital letter, does not end with punctuation and is 50 characters or less long. See https://cbea.ms/git-commit/
• If applicable: Created new issues if this PR does not fix the issue completely/there is further work to be done

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.32%. Comparing base (920b82b) to head (e5770b8).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #335   +/-   ##
=======================================
  Coverage   97.32%   97.32%           
=======================================
  Files          64       64           
  Lines        7920     7922    +2     
=======================================
+ Hits         7708     7710    +2     
  Misses        212      212           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[stveit]

I suppose the "_" to "-" conversion becomes redundant once all of the necessary aliases are added

[johannaengland]

I suppose the "_" to "-" conversion becomes redundant once all of the necessary aliases are added

Yes, but I am not sure if these aliases are all that are needed to be able to remove that conversion. So I'll keep it for now, but I'll add an issue for discussion