We create tox environments local-conda-forge-environment[-optional].
In contrast to ...-standard and ...-minimal, they use the files $SAGE_ROOT/environment*.yml (generated by bootstrap) to set up the conda environment.

To test locally:

  tox -e local-conda-forge-environment
  tox -e local-conda-forge-environment-optional

We also add them to the GH Actions workflow to ensure that the files environment*.yml are generated correctly.

See also:

• Fixes for the conda-for-Sage-developers installation method, add GH Actions workflow #30845, which adds tests for the files SAGE_ROOT/src/environment*.yml

CC: @tobiasdiez @isuruf @kliem

Component: porting

Author: Matthias Koeppe

Branch/Commit: b998c84

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/31099