Add a python version to pycares constraint

[mdellweg]

This should allow to install newer version if a recent version of python is used. It also documents nicely when exactly we can remove the constraint again.

[patchback]

Backport to 3.49: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply e864761 on top of patchback/backports/3.49/e864761b326616ff63e448feebce51addddc1b61/pr-6722

Backporting merged PR #6722 into 3.73

1. Ensure you have a local repo clone of your fork. Unless you cloned it
   from the upstream, this would be your origin remote.
2. Make sure you have an upstream repo added as a remote too. In these
   instructions you'll refer to it by the name upstream. If you don't
   have it, here's how you can add it:

   $ git remote add upstream https://github.com/pulp/pulpcore.git

3. Ensure you have the latest copy of upstream and prepare a branch
   that will hold the backported code:

   $ git fetch upstream
   $ git checkout -b patchback/backports/3.49/e864761b326616ff63e448feebce51addddc1b61/pr-6722 upstream/3.49

4. Now, cherry-pick PR Add a python version to pycares constraint #6722 contents into that branch:

   $ git cherry-pick -x e864761b326616ff63e448feebce51addddc1b61

   If it'll yell at you with something like fatal: Commit e864761b326616ff63e448feebce51addddc1b61 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x e864761b326616ff63e448feebce51addddc1b61

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Add a python version to pycares constraint #6722 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.49/e864761b326616ff63e448feebce51addddc1b61/pr-6722

7. Create a PR, ensure that the CI is green. If it's not — update it so that
   the tests and any other checks pass. This is it!
   Now relax and wait for the maintainers to process your pull request
   when they have some cycles to do reviews. Don't worry — they'll tell you if
   any improvements are necessary when the time comes!

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[patchback]

Backport to 3.63: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply e864761 on top of patchback/backports/3.63/e864761b326616ff63e448feebce51addddc1b61/pr-6722

Backporting merged PR #6722 into 3.73

1. Ensure you have a local repo clone of your fork. Unless you cloned it
   from the upstream, this would be your origin remote.
2. Make sure you have an upstream repo added as a remote too. In these
   instructions you'll refer to it by the name upstream. If you don't
   have it, here's how you can add it:

   $ git remote add upstream https://github.com/pulp/pulpcore.git

3. Ensure you have the latest copy of upstream and prepare a branch
   that will hold the backported code:

   $ git fetch upstream
   $ git checkout -b patchback/backports/3.63/e864761b326616ff63e448feebce51addddc1b61/pr-6722 upstream/3.63

4. Now, cherry-pick PR Add a python version to pycares constraint #6722 contents into that branch:

   $ git cherry-pick -x e864761b326616ff63e448feebce51addddc1b61

   If it'll yell at you with something like fatal: Commit e864761b326616ff63e448feebce51addddc1b61 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x e864761b326616ff63e448feebce51addddc1b61

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Add a python version to pycares constraint #6722 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.63/e864761b326616ff63e448feebce51addddc1b61/pr-6722

7. Create a PR, ensure that the CI is green. If it's not — update it so that
   the tests and any other checks pass. This is it!
   Now relax and wait for the maintainers to process your pull request
   when they have some cycles to do reviews. Don't worry — they'll tell you if
   any improvements are necessary when the time comes!

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.