Updating Packages

[allan]

Hi there! I am new to software development, but I would like to contribute. I 
want to start by updating some rust packages to newer versions.<br>

So far I have just been making scheme files in a seperate directory and running 
"guix build -f $SCHEME_FILE". I am trying to follow the [guidlines in the 
manual](https://guix.gnu.org/manual/en/html_node/Contributing.html), but git is 
still new to me and I am a little confused how to make this all work.

What should I do to get package builds to recognize the updates I make to 
dependencies?