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.