Invite users to the workspace programmatically

[AleksanderWWW]

Before submitting checklist

• Did you update the CHANGELOG? (not for test updates, internal changes/refactors or CI/CD setup)
• Did you ask the docs owner to review all the user-facing changes?

[codecov]

Codecov Report

Patch coverage: 82.92% and project coverage change: -0.05 ⚠️

Comparison is base (b3df4c5) 79.65% compared to head (ef9c87e) 79.61%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1333      +/-   ##
==========================================
- Coverage   79.65%   79.61%   -0.05%     
==========================================
  Files         276      276              
  Lines       13530    13571      +41     
==========================================
+ Hits        10777    10804      +27     
- Misses       2753     2767      +14     

Flag	Coverage Δ
py3.7	73.01% <82.92%> (-6.13%)	⬇️
py3.9	?
ubuntu	73.01% <82.92%> (-6.40%)	⬇️
unit	73.01% <82.92%> (-0.66%)	⬇️

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

Impacted Files	Coverage Δ
src/neptune/management/internal/api.py	88.72% <77.77%> (-1.66%)	⬇️
src/neptune/management/internal/utils.py	96.15% <87.50%> (-3.85%)	⬇️
src/neptune/management/exceptions.py	97.80% <100.00%> (+0.15%)	⬆️

... and 7 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[normandy7]

For the role, can the end-user pass "admin"/"member", or you need to use the enums?

[AleksanderWWW]

For the role, can the end-user pass "admin"/"member", or you need to use the enums?

The spec wasn't clear about this, so in this design I decided that the enum will be required.
This way the code is cleaner imo and there's no need to check separately if the value passed by a user is correct