feat: Add missing github enterprise importer and domains meta fields

[lrstanley]

Adds two of the missing fields, github_enterprise_importer and domains, which are now included with the public meta endpoint. Also fixed some minor capitalization errors.

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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 (3250afd).
Report is 35 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3121      +/-   ##
==========================================
- Coverage   97.72%   92.88%   -4.84%     
==========================================
  Files         153      170      +17     
  Lines       13390    11423    -1967     
==========================================
- Hits        13085    10610    -2475     
- Misses        215      723     +508     
  Partials       90       90              

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[gmlewis]

Thank you, @lrstanley !
LGTM.
Merging.