CI: Remove warning raising after new matplotlib release
- [ ] xref #31562   
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

seems CI is broken after the new release of matplotlib
xref #30588  Hello @charlesdong1991! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:



There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2020-02-02 16:12:22 UTC this looks better simpler, i didn't notice this `skip_if_no` decorator, thanks for the tip! @jreback 

since it uses `>=` in `safe_import`, so setting the `min_version` to `3.1.3`, it works locally for me ping @jreback  thanks for pro-actively fixing this @charlesdong1991 !