Set default pull strategy to ff-only, because git 2.27 complains if unset

Rebase won't let you pull with unstaged changes, and I rarely want to
make a merge commit

.config/git/config

@@ -1,6 +1,8 @@
 [user]
 	email = adam@adamgoldsmith.name
 	name = Adam Goldsmith
+[pull]
+	ff = only
 [push]
 	default = simple
 [core]