CI: pin fsspec
Hopefully fixes new Windows py37_np17 failures
ok exciting, ping on green. @simonjayhawkins we *may* want to do this for 1.2.5 sure. maybe best to just backport ci changes to 1.3 for now, and i'll go through the backports and backport any needed to 1.2.5 The azure failure timed out on this latest run, but succeeded on previous commit, so greenish thanks @mzeitlin11 
 @meeseeksdev backport 1.3.x Something went wrong ... Please have  a look at my logs. @meeseeksdev backport 1.2.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 1.2.x
$ git pull
```

2. Cherry pick the first parent branch of the this PR on top of the older branch:
```
$ git cherry-pick -m1 89ef88a3a0b8c4e2670d8b020df7156878e27306
```

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

```
$ git commit -am 'Backport PR #42023: CI: pin fsspec'
```

4. Push to a named branch :

```
git push YOURFORK 1.2.x:auto-backport-of-pr-42023-on-1.2.x
```

5. Create a PR against branch 1.2.x, I would have named this PR:

> "Backport PR #42023 on branch 1.2.x"

And apply the correct labels and milestones.

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

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