Whenever I add a package now from a git repo I receive the same error:
**Project has invalid dependencies
Not ‘git’ executable was found. Please install Git on your system and restart Unity.
**
Git has been installed on the machine for a long, long time, but I reinstalled just to be certain I didn’t miss anything and to make sure the cmd was added to the system PATH variable.
In my case git.exe and git-lfs.exe files were in different Folder (C:\Program Files\Git\cmd) I showed the new related paths in unity and pushed the button Find System Git. and it worked.