Make git requirement explicit

[DieFinsternis]

I got interested in this plugin for our codebase, but when I wanted to try it out Claude told me that it conceptionally relies heavily on git and that it isn't feasable for my project since it isn't a git repo.
When I read through the plugin description not once did I get the idea you'd parse the projects history and as such did not expect the SCM to matter. That was actually what got me interested in the first place: the description read tool neutral.