Add 'repository_import' event

[ldez]

Add repository_import event.

GitHub API docs: https://docs.github.com/en/developers/webhooks-and-events/webhooks/webhook-events-and-payloads#repository_import

[codecov]

Codecov Report

Merging #2364 (3d7a799) into master (8947206) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2364   +/-   ##
=======================================
  Coverage   98.05%   98.05%           
=======================================
  Files         119      119           
  Lines       10503    10505    +2     
=======================================
+ Hits        10299    10301    +2     
  Misses        140      140           
  Partials       64       64           

Impacted Files	Coverage Δ
github/messages.go	100.00% <ø> (ø)
github/event.go	100.00% <100.00%> (ø)
github/event_types.go	100.00% <100.00%> (ø)

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[gmlewis]

Thank you, @ldez !
One minor tweak, please, then we should be ready for a second LGTM+Approval from any other contributor to the repo before merging.

[gmlewis]

Thank you, @ldez ! Wow, that was fast! 😄

Awaiting second LGTM+Approval from any other contributor to the repo before merging.

[raynigon]

LGTM

[gmlewis]

LGTM

Thank you, @raynigon !
Merging.