CI: Format isort output for azure
- [x] closes #27179
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

Current behaviour on master of isort formatting:
![image](https://user-images.githubusercontent.com/16733618/69010035-12c41f80-0953-11ea-8e70-4d17e8dec943.png)


Finishing up stale PR @https://github.com/pandas-dev/pandas/pull/27334

Since we are now using Github Actions ill update this.

Before this change output is:
![image](https://user-images.githubusercontent.com/16733618/69905823-5b4af680-13b1-11ea-9899-dfdd003411d3.png)
 Output now looks better - but I need to fix the return code 
![image](https://user-images.githubusercontent.com/16733618/69906210-d44d4c80-13b7-11ea-8169-888b40796722.png)
 Related failures: https://github.com/pandas-dev/pandas/issues/30031 CI finally passed. @datapythonista @WillAyd to merge  Thanks @WillAyd 