Rebranding to mamba-gator

[fcollonval]

This follows https://github.com/mamba-org/gator/issues/88#issuecomment-727539752

[github-actions[bot]]

:point_left: Launch a binder notebook on the branch mamba-org/gator/fcollonval/issue88

[coveralls]

Pull Request Test Coverage Report for Build 376030498

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 4 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.3%) to 69.384%

---

Files with Coverage Reduction	New Missed Lines	%
mamba_gator/envmanager.py	4	88.14%
<!--	Total:	4		-->

Totals
Change from base Build 375977983:	-0.3%
Covered Lines:	737
Relevant Lines:	972

---

💛 - Coveralls