Add pandas-genomics to the ecosystem list
- [x] closes #xxxx
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Added [as suggested here](https://github.com/pandas-dev/pandas/pull/36987#pullrequestreview-505157583).