DOC: Added check for standard pandas reference
- [x] xref #32316
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

As suggested by @datapythonista , I've added checks in `ci/code_checks.sh` to look if the pandas is being referenced in a standardized way i.e pandas, not *pandas* or Pandas