Use released ixmp4 v0.10 in CI

[khaeru]

Parallel to iiasa/ixmp#576.

How to review

• Read the diff.
• Note that the CI checks all pass. In particular look at this workflow run from the 'pull_request' trigger, and not the failed jobs from 'pull_request_target'.

PR checklist

• Continuous integration checks all ✅
• Add or expand tests; coverage checks both ✅
• Add, expand, or update documentation. N/A; CI changes only
• Update release notes.
• (After approval, before merge) Drop the TEMPORARY commit.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.0%. Comparing base (fc8f9e0) to head (ee8c9fc).
Report is 4 commits behind head on main.

❗ Current head ee8c9fc differs from pull request most recent head 7e0a756

Please upload reports for the commit 7e0a756 to get more accurate results.

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #941     +/-   ##
=======================================
+ Coverage   90.6%   96.0%   +5.3%     
=======================================
  Files         53      53             
  Lines       4987    4988      +1     
=======================================
+ Hits        4521    4791    +270     
+ Misses       466     197    -269     

see 12 files with indirect coverage changes

[glatterf42]

Thanks for this, too, lgtm :)

[glatterf42]

This makes me wonder whether the same is necessary in ixmp, but I don't see ixmp4 in our RTD requirements file there :)