.chezmoiroot
If a file called .chezmoiroot exists in the root of the source directory then
the source state is read from the directory specified in .chezmoiroot
interpreted as a relative path to the source directory. .chezmoiroot is read
before all other files in the source directory.
Warning
If you use this approach, you must move all other "source root" files such
as .chezmoi.$FORMAT.tmpl into your new root.