Functionality to audit conda environment files

[JosiahParry]

This pull request proposes a new function to audit Conda environment yaml files. This function supports environment.yml files that contain both pip and conda dependencies. If there are other types of package source dependencies that can be incorporated in an environment.yml I will have missed them. Unlike audit_renv_lock() and audit_req_txt(), this function permits the user to provide their own file name. This is because there is greater variability in the naming conventions of conda environment files (e.g. https://github.com/vithursant/deep-learning-conda-envs).

This pull request makes the following changes:

• Creates new function audit_env_yml()
• Documents the new function
• Creates a testthat test for the new function
  • A sample environment.yml file is also included in the testthat/ to support the test.

cc @bhamail / @DarthHater / @brittanybelle / @adrianpowell / @csgillespie

[csgillespie]

Thanks @JosiahParry A few things

• Would you bump the version and add a NEWS.md
• Update the DESCRIPTION file and make yourself an author - ctb to aut
• I probably won't look at this until next week. But as I have to resubmit to CRAN in early Jan (a bad example), I'll try and make sure this gets change gets included.

and finally, thanks!

Oh and congratulations on using the superior assignment operator = vs <-

[JosiahParry]

Just for your sake I ran a find and replace all for the assignment arrow 😉 This is my way of not working today 😝 I'll go ahead and make the changes.

Will also try and make expect_secure_renv/req/env functions as well. I'd like to have an up and running example of automated checks with testthat soon. I think it'll be exceptionally useful for those security conscious orgs (even if it'll always return 0 for R 😬 )

[DarthHater]

Wild! @JosiahParry , if it interests you, we originally designed this project: https://github.com/sonatype-nexus-community/jake to work with Conda, we took a slightly different approach. If you like writing Python, you are always welcome over there, too!