Add enums for webhook payloads action field

[prnvbn]

Relevant Issue: #3127

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.88%. Comparing base (2b8c7fa) to head (7fb9e96).
Report is 43 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3136      +/-   ##
==========================================
- Coverage   97.72%   92.88%   -4.84%     
==========================================
  Files         153      170      +17     
  Lines       13390    11426    -1964     
==========================================
- Hits        13085    10613    -2472     
- Misses        215      723     +508     
  Partials       90       90              

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[gmlewis]

Ah! Now I understand better the scope of this breaking API change.
I apologize that I couldn't quite visualize fully what we were discussing before.

I would like @willnorris to weigh in on this PR to get his thoughts on the value of this change vs the breaking nature of it (and therefore the impact on developers) before we proceed further.

[prnvbn]

Makes sense!

[prnvbn]

@gmlewis @willnorris any update on the PR?