CI: Fix Assign CI not working with quotes
- [x] closes #29768 
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

Examples(all three passed)
![image](https://user-images.githubusercontent.com/47963215/72952081-a6481100-3d45-11ea-8845-338f2a2f17a4.png)

