CI: Fix actions-310 testing 3.9 instead of 3.10
- [x] tests added / passed


test_write_ignoring_index? LGTM cc @jreback should get us back to green? > should get us back to green?

Not necessarily. Just an error in our CI configs. Azure failures are the flaky timeouts Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

```
git checkout 1.4.x
git pull
```

2. Cherry pick the first parent branch of the this PR on top of the older branch:
```
git cherry-pick -m1 573805782558885b04efc59a49ff3090ca783ef5
```

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

```
git commit -am 'Backport PR #45581: CI: Fix actions-310 testing 3.9 instead of 3.10'
```

4. Push to a named branch:

```
git push YOURFORK 1.4.x:auto-backport-of-pr-45581-on-1.4.x
```

5. Create a PR against branch 1.4.x, I would have named this PR:

> "Backport PR #45581 on branch 1.4.x (CI: Fix actions-310 testing 3.9 instead of 3.10)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the `Still Needs Manual Backport` label once the PR gets merged.

If these instructions are inaccurate, feel free to [suggest an improvement](https://github.com/MeeseeksBox/MeeseeksDev).
                 @meeseeksdev backport 1.4.x Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

```
git checkout 1.4.x
git pull
```

2. Cherry pick the first parent branch of the this PR on top of the older branch:
```
git cherry-pick -m1 573805782558885b04efc59a49ff3090ca783ef5
```

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

```
git commit -am 'Backport PR #45581: CI: Fix actions-310 testing 3.9 instead of 3.10'
```

4. Push to a named branch:

```
git push YOURFORK 1.4.x:auto-backport-of-pr-45581-on-1.4.x
```

5. Create a PR against branch 1.4.x, I would have named this PR:

> "Backport PR #45581 on branch 1.4.x (CI: Fix actions-310 testing 3.9 instead of 3.10)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the `Still Needs Manual Backport` label once the PR gets merged.

If these instructions are inaccurate, feel free to [suggest an improvement](https://github.com/MeeseeksBox/MeeseeksDev).
                