feat: Implement missing push rules

[srgustafson8]

Adds support for the missing Push Rules - Restrict file path length, Restrict file extensions and Restrict file size with tests.

Closes #3274

[srgustafson8]

Tests output:

testing .
?       github.com/google/go-github/v65/test/integration        [no test files]
        github.com/google/go-github/v65/test/fields             coverage: 0.0% of statements
ok      github.com/google/go-github/v65/github  8.592s  coverage: 99.4% of statements
testing example
        github.com/google/go-github/v65/example/codespaces/newusersecretwithxcrypto             coverage: 0.0% of statements
        github.com/google/go-github/v65/example/appengine               coverage: 0.0% of statements
        github.com/google/go-github/v65/example/basicauth               coverage: 0.0% of statements
        github.com/google/go-github/v65/example/codespaces/newreposecretwithxcrypto             coverage: 0.0% of statements
        github.com/google/go-github/v65/example/actionpermissions               coverage: 0.0% of statements
        github.com/google/go-github/v65/example/migrations              coverage: 0.0% of statements
        github.com/google/go-github/v65/example/commitpr                coverage: 0.0% of statements
        github.com/google/go-github/v65/example/listenvironments                coverage: 0.0% of statements
        github.com/google/go-github/v65/example/newfilewithappauth              coverage: 0.0% of statements
        github.com/google/go-github/v65/example/newrepo         coverage: 0.0% of statements
        github.com/google/go-github/v65/example/ratelimit               coverage: 0.0% of statements
        github.com/google/go-github/v65/example/newreposecretwithxcrypto                coverage: 0.0% of statements
        github.com/google/go-github/v65/example/simple          coverage: 0.0% of statements
        github.com/google/go-github/v65/example/tagprotection           coverage: 0.0% of statements
        github.com/google/go-github/v65/example/tokenauth               coverage: 0.0% of statements
        github.com/google/go-github/v65/example/topics          coverage: 0.0% of statements
testing scrape
ok      github.com/google/go-github/scrape      (cached)        coverage: 59.4% of statements
        github.com/google/go-github/scrape/example/scrape               coverage: 0.0% of statements
testing tools
ok      tools/metadata  (cached)        coverage: 81.7% of statements```

[gmlewis]

Thank you, @srgustafson8 !
Just a few minor tweaks, please, then we should be ready for a second LGTM+Approval from any other contributor to this repo before merging.

If you have a moment, would you mind taking a look at some of the other outstanding PRs and give them code reviews, please? Of note is #3254 where the author is expressing desire to merge ASAP. Thank you!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.01%. Comparing base (2b8c7fa) to head (14dddd8).
Report is 128 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3294      +/-   ##
==========================================
- Coverage   97.72%   93.01%   -4.72%     
==========================================
  Files         153      171      +18     
  Lines       13390    11777    -1613     
==========================================
- Hits        13085    10954    -2131     
- Misses        215      729     +514     
- Partials       90       94       +4     

☔ View full report in Codecov by Sentry.
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[gmlewis]

Thank you, @srgustafson8 !
LGTM.

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

[tomfeigin]

LGTM

[air-hand]

LGTM

[gmlewis]

Thank you, @tomfeigin and @air-hand !
Merging.