[CI] Remove python2 from mac and windows environments

We only use python2 on Linux for older versions of mercurial.

.github/workflows/taskcluster.yml

@@ -9,7 +9,6 @@ jobs:
       PATH: /usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/Frameworks/Python.framework/Versions/2.7/bin
     steps:
       - uses: actions/checkout@v3
-      - run: sudo -H python2.7 -m pip install pip==20.3.4 wheel==0.37.0 --upgrade
       - uses: actions/setup-python@v4
         with:
           python-version: '3.9.14'

CI/msys.py

@@ -113,7 +113,6 @@ def __init__(self, name):
             'pkill gpg-agent',
             'pkill dirmngr',
             'rm -rf /var/cache/pacman/pkg',
-            'python2.7 -m pip install pip==20.3.4 wheel==0.37.1 --upgrade',
             'python3 -m pip install pip==22.2.2 wheel==0.37.1 --upgrade',
             'mv {}/{}/bin/{{mingw32-,}}make.exe'.format(msys(cpu), mingw(cpu)),
             'tar -c --hard-dereference {} | zstd -c > msys2.tar.zst'.format(
@@ -146,8 +145,6 @@ def mingw_packages(pkgs):
         packages = mingw_packages([
             'curl',
             'make',
-            'python2',
-            'python2-pip',
             'python3',
             'python3-pip',
         ])