make action not reliant on docker

hi there!

i was wondering if it would be possible to not make this action reliant on docker to run. i am attempting to use ghcommit in an environment without docker (using nothing-but-nix to remove everything non-nix from the github base image to increase available space).

this entire action seems to just run a single go binary, so it seems pretty easy for this to just download and run if i'm not mistaken.