Update developer documentation to specify pushing to repo must be done from within the conda environment

[Sparrow0hawk]

Occasionally people have had problems pushing their commits to the repo because the repo is configured with git-lfs but they are doing git push from outside the ramp-ua conda environment.

We don't cover this requirement in any of our documentation so i'll look to clarify this more explicitly in our documentation.

[ciupava]

Great, thanks!

[ciupava]

If it helps clarifying, this was the error message I was getting when trying to push to the remote repository:

git push

This repository is configured for Git LFS but 'git-lfs' was not found on your path. If you no longer wish to use Git LFS, remove this hook by deleting .git/hooks/pre-push.

error: failed to push some refs to 'https://github.com/Urban-Analytics/RAMP-UA/'```
I think that @mfbenitezp had this issue in the past as well.