ENH: Add progress_bar_type argument in read_gbq
- [x] closes #29857 
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Should we just add kwargs here to pass along instead? I think there are a few other keywords that aren't specifically stated; probably easier to just pass through > Should we just add kwargs here to pass along instead? I think there are a few other keywords that aren't specifically stated; probably easier to just pass through

no 

explicit is better than implicit  cc @tswast 

does this require a min version? thanks @charlesdong1991 

@tswast also happy to take a new min version of pandas-gbq if you need / want for 1.0