Update games/packages/minecraft.scm to latest version?

I am going to prefix this by saying I am relativly new to GNU Guix. I have used the distribution for under a week. I commonly use multimc to manage my Minecraft instances, but since migrated accounts to Microsoft are now the norm, it would likely be for the best to update this package to 0.6.14 from 0.6.12

I made the changes that should be nessecary for it to work, though I do not know how to test-build the package properly once again from being an ameatur to the GNU Guix distribution. I would reccommend you try to build it.

Thank you for your time, Celestia