feat(events)!: support merge queue for GitHub SCM

[ecrupper]

ref: go-vela/community#1061

Breaking Changes

• New database field for repos merge_queue_events, which will be a list of events that the merge_group event build will report to. This is necessary to preserve normal required status checks while also allowing for a merge queue. Vela is event-based in its status checks, not job-name-based. So required checks from a pull_request build will need to be targeted for merge_group events.

Opt In

Ultimately, this is opt-in functionality. If users do not supply any override events, then Vela will behave the exact same.

Pipeline Changes

steps:
  - name: tests
     image: golang:latest
     ruleset:
        event: [ pull_request, merge_group ] 
     commands:
       - go test ./...

Auto Cancel

Determining stale builds for a merge group is different than normal builds. Stale builds are defined as builds that are pending or running that are part of the merge group and also include a build that failed. There's a more detailed description of this in the reference link.

[codecov]

Codecov Report

❌ Patch coverage is 23.20261% with 235 lines in your changes missing coverage. Please review.
✅ Project coverage is 58.29%. Comparing base (0ea4d84) to head (a600793).

Files with missing lines	Patch %	Lines
api/build/cancel.go	0.00%	76 Missing ⚠️
api/webhook/post.go	0.00%	57 Missing ⚠️
scm/github/webhook.go	0.00%	48 Missing and 1 partial ⚠️
database/testutils/api_resources.go	0.00%	26 Missing ⚠️
api/repo/create.go	0.00%	7 Missing ⚠️
api/repo/update.go	0.00%	7 Missing ⚠️
api/build/restart.go	0.00%	4 Missing ⚠️
scm/github/repo.go	88.88%	2 Missing and 2 partials ⚠️
api/build/update.go	0.00%	2 Missing ⚠️
api/build/auto_cancel.go	0.00%	1 Missing ⚠️
... and 2 more

❌ Your project check has failed because the head coverage (58.29%) is below the target coverage (90.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1343      +/-   ##
==========================================
- Coverage   58.36%   58.29%   -0.07%     
==========================================
  Files         645      644       -1     
  Lines       24864    24921      +57     
==========================================
+ Hits        14511    14527      +16     
- Misses       9681     9719      +38     
- Partials      672      675       +3     

Files with missing lines	Coverage Δ
api/types/repo.go	97.98% <100.00%> (+0.06%)	⬆️
database/repo/table.go	100.00% <ø> (ø)
database/types/repo.go	89.02% <100.00%> (+0.13%)	⬆️
mock/server/repo.go	0.00% <ø> (ø)
scm/github/github.go	49.20% <ø> (ø)
scm/github/merge_queue.go	100.00% <100.00%> (ø)
api/build/auto_cancel.go	37.09% <0.00%> (+18.24%)	⬆️
compiler/native/compile.go	73.60% <0.00%> (ø)
router/build.go	0.00% <0.00%> (ø)
api/build/update.go	0.00% <0.00%> (ø)
... and 8 more

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