Added recipe for 'genv' and 'jupyterlab_genv'

[razrotenberg]

Checklist

• [x] Title of this PR is meaningful: e.g. "Adding my_nifty_package", not "updated meta.yaml".
• [x] License file is packaged (see here for an example).
• [x] Source is from official source.
• [x] Package does not vendor other packages. (If a package uses the source of another package, they should be separate packages or the licenses of all packages need to be packaged).
• [x] If static libraries are linked in, the license of the static library is packaged.
• [x] Package does not ship static libraries. If static libraries are needed, follow CFEP-18.
• [x] Build number is 0.
• [x] A tarball (url) rather than a repo (e.g. git_url) is used in your recipe (see here for more details).
• [x] GitHub users listed in the maintainer section have posted a comment confirming they are willing to be listed there.
• [x] When in trouble, please check our knowledge base documentation before pinging a team.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipes/genv, recipes/jupyterlab_genv) and found it was in an excellent condition.

[razrotenberg]

@conda-forge-admin please ping conda-forge/staged-recipes

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-webservice.

I was asked to ping @conda-forge/staged-recipes and so here I am doing that.

[razrotenberg]

@conda-forge-admin conda-forge/staged-recipes

[razrotenberg]

@conda-forge-admin please ping conda-forge/staged-recipes

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-webservice.

I was asked to ping @conda-forge/staged-recipes and so here I am doing that.