feat!: Update deprecated endpoints in github/action_variables.go

[HariCharanK]

Fixes:
#3103

BREAKING-CHANGE: The following endpoints now take owner and repo names instead of an integer repo ID:

• ActionsService.ListEnvVariables
• ActionsService.GetEnvVariable
• ActionsService.CreateEnvVariable
• ActionsService.UpdateEnvVariable
• ActionsService.DeleteEnvVariable

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.87%. Comparing base (2b8c7fa) to head (eefe111).
Report is 23 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3104      +/-   ##
==========================================
- Coverage   97.72%   92.87%   -4.86%     
==========================================
  Files         153      170      +17     
  Lines       13390    11403    -1987     
==========================================
- Hits        13085    10590    -2495     
- Misses        215      723     +508     
  Partials       90       90              

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[gmlewis]

Thank you, @HariCharan-001 !
LGTM.

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

[HariCharanK]

Hi @gmlewis
The second approval is still pending. Just letting you know, in case.

Can you tag anyone you know ?

[gmlewis]

I try to not bother volunteers since this repo has a rather high traffic of PRs (in my opinion).
Feel free to ask any developer you know to provide a code review.

[gmlewis]

This is holding up other PRs like #3109.
Merging.