Makefile: use python3 instead of python

[bfontaine]

Ubuntu doesn’t have a python executable; it’s either python2 or python3.

[bfontaine]

The failure seems to be unrelated:

C:\hostedtoolcache\windows\Python\3.10.10\x64\python3.exe: No module named pytest
  mingw[32](https://github.com/python-babel/babel/actions/runs/4315580116/jobs/7530168374#step:6:33)-make: *** [makefile:2: test] Error 1
  py310: exit 2 (9.42 seconds) D:\a\babel\babel> make clean-cldr test pid=6116

[codecov]

Codecov Report

Merging #984 (5dbc4be) into master (0ce196f) will decrease coverage by 1.37%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #984      +/-   ##
==========================================
- Coverage   90.94%   89.57%   -1.37%     
==========================================
  Files          25       25              
  Lines        4352     4356       +4     
==========================================
- Hits         3958     3902      -56     
- Misses        394      454      +60     

Impacted Files	Coverage Δ
babel/localtime/_win32.py	25.92% <0.00%> (-37.04%)	⬇️
babel/localtime/_helpers.py	42.30% <0.00%> (-19.24%)	⬇️
babel/support.py	76.95% <0.00%> (-8.37%)	⬇️
babel/localtime/__init__.py	75.00% <0.00%> (-8.34%)	⬇️
babel/dates.py	86.37% <0.00%> (-0.87%)	⬇️
babel/localedata.py	95.04% <0.00%> (-0.83%)	⬇️
babel/messages/frontend.py	86.64% <0.00%> (-0.75%)	⬇️
babel/core.py	96.54% <0.00%> (-0.29%)	⬇️
babel/messages/catalog.py	95.71% <0.00%> (ø)

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[akx]

The failure seems to be unrelated:

C:\hostedtoolcache\windows\Python\3.10.10\x64\python3.exe: No module named pytest

I don't think it is unrelated; that's not the tox-created virtualenv's python.

[bfontaine]

You’re right.

According to tox-dev/tox#2801 on Windows you have to use python because python3 doesn’t exist, while on Debian (and so Ubuntu) you have to use python3 because python doesn’t exist. However, if you create a virtual environment with virtualenv or similar, you should have a python executable anyway, so this PR is not relevant.