editorconfig: Unset maximum line length for .git
An editorconfig's asterix section applies to the whole file tree, including the .git folder. The Git commit message dialog is a temporary file named .git/COMMIT_EDITMSG, which the editorconfig applies to.
To avoid having the line length of commit messages changed to 100 chars, add a rule to specifically unset the max_line_length for the .git folder.