CI: fewer workers on windows
- [x] closes #42236

Seeing if this helps for #42236


set this on all the windows builds I've milestoned 1.3 or we can instead backport later if this improves things.

since it's only CI related, no harm in backporting though. thanks @mzeitlin11  @meeseeksdev backport 1.3.x Something went wrong ... Please have  a look at my logs.