get_updates: Update the retriever's dataset scripts to the most recent versions.
Description
This function will check if the version of the retriever's scripts in your local
directory ‘~/.retriever/scripts/’ is up-to-date with the most recent official
retriever release. Note it is possible that even more updated scripts exist
at the retriever repository https://github.com/weecology/retriever/tree/master/scripts
that have not yet been incorperated into an official release, and you should
consider checking that page if you have any concerns.