CI: catch warning produced in resample
- [x] closes #42814
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [ ] whatsnew entry

@jreback gentle ping gets us back to green (unrelated windows timeout) do we need to backport this? if we dont want to show users FutureWarnings then yah but this is in a test so nbd i guess