CI always runs with Python 3.13 (ignores specification)

[dmitry-kabanov]

Describe the bug
I have noticed that GitHub Actions always use Python 3.13 - precisely, conda creates an environment always with the default version of Python, although it is specified via the python-version key.

Expected behavior
Each job must use the specified Python version.

To Reproduce
See GitHub Actions reports - particularly, section "Show info" shows that the version of Python is always 3.13. For example, in the output of the job qa-ubuntu-conda-3.10

python is /home/runner/miniconda3/envs/test/bin/python
Python 3.13.1

In spite of the fact that it for this job it must be Python 3.10.

[dmitry-kabanov]

Local branch for this is github-actions-fix-python-version, in the um02 directory.