Update minimum version of genno

[glatterf42]

As noted by @awais307, we should bump the minimum required version of genno to the one that introduces genno.operator.

How to review

• Read the diff and note that the CI checks all pass.

PR checklist

• Continuous integration checks all ✅
• [ ] Add or expand tests; coverage checks both ✅ Just bumping dependency
• [ ] Add, expand, or update documentation. Just bumping dependency
• [ ] Update release notes. Just bumping dependency

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (49ec67d) 98.9% compared to head (aa75739) 98.2%.

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #514     +/-   ##
=======================================
- Coverage   98.9%   98.2%   -0.8%     
=======================================
  Files         44      44             
  Lines       4795    4795             
=======================================
- Hits        4744    4709     -35     
- Misses        51      86     +35     

see 3 files with indirect coverage changes

[khaeru]

This should also go in the release notes. For examples, see:

ixmp/RELEASE_NOTES.rst

Line 75 in 49ec67d

- Adjust to genno 1.12 and set this as the minimum required version for :mod:`ixmp.reporting <ixmp.report>` (:pull:`451`).

ixmp/RELEASE_NOTES.rst

Lines 91 to 94 in 49ec67d

	- Minimum requirements are increased for dependencies (:pull:`435`):
	- Python 3.7 or greater. Python 3.6 reached end-of-life on 2021-12-31.
	- Pandas 1.2 (2020-12-26) or greater, the oldest version with a minimum Python version of 3.7.

[glatterf42]

Merging this since the coverage is not affected, codecov just didn't register the reports correctly.