Clarified CI Job Token auth. caveats

[axl89]

See issue #1620

[nejch]

Thanks for the quick PR @axl89! Just a small suggestion.

Also, it is likely CI will fail as we use commit messages to generate changelogs.

Maybe amending your commit message to docs(api): clarifiy CI Job Token auth. caveats would help :)

[codecov-commenter]

Codecov Report

Merging #1624 (746c25f) into master (7753fa2) will increase coverage by 3.88%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1624      +/-   ##
==========================================
+ Coverage   87.95%   91.84%   +3.88%     
==========================================
  Files          74       74              
  Lines        4294     4294              
==========================================
+ Hits         3777     3944     +167     
+ Misses        517      350     -167     

Flag	Coverage Δ
cli_func_v4	81.85% <ø> (ø)
py_func_v4	80.88% <ø> (?)
unit	83.67% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
gitlab/base.py	89.69% <0.00%> (+0.60%)	⬆️
gitlab/client.py	89.79% <0.00%> (+2.80%)	⬆️
gitlab/types.py	96.42% <0.00%> (+3.57%)	⬆️
gitlab/v4/objects/groups.py	87.20% <0.00%> (+4.00%)	⬆️
gitlab/mixins.py	91.12% <0.00%> (+4.17%)	⬆️
gitlab/v4/objects/projects.py	86.69% <0.00%> (+5.03%)	⬆️
gitlab/v4/objects/issues.py	88.00% <0.00%> (+5.33%)	⬆️
gitlab/v4/objects/labels.py	93.47% <0.00%> (+6.52%)	⬆️
gitlab/v4/objects/users.py	98.43% <0.00%> (+6.77%)	⬆️
gitlab/v4/objects/deploy_keys.py	100.00% <0.00%> (+8.69%)	⬆️
... and 10 more

[nejch]

I made the quick fix in the commit message. Thanks again @axl89!