must install git before installing stenv

[fsc137-cfa]

Installing stenv on a fresh installation of Ubuntu 22.04, the "conda env create" command failed at "Installing pip dependencies", resulting in the error sequence in this file:
piperror.txt

My Linux installation at that point did not have "git" installed, so I did:

sudo apt-get install git-all

and then removed the failed stenv environment:

conda env remove -n stenv

and re-ran the conda env create command and this time it worked.

[zacharyburnett]

Good catch; this appears to be due to stistools using relic to retrieve the version tag at install time, by cloning into a git submodule. After spacetelescope/stistools#145 is merged and released in a new stistools version, this issue should be resolved.