MAINTAINERS: name the ext4 dev branch

The ext4 T: entry names the repository without a branch, so tools that
default to the repository's HEAD select master, which still points at a
merge from October 2020 (96485e446260).  Development happens on dev,
which is also the branch linux-next merges.  Name it.

The Sashiko review bot, for one, falls back to HEAD this way and has
been reviewing ext4 patches against that tree.  Its review of an EA
inode refcount fix reported a Critical double decrement and an
undefined function after applying the patch to that stale baseline;
neither holds on dev.

Link: https://lore.kernel.org/all/20260916072420.316321F000FF@smtp.kernel.org/
Signed-off-by: Matthias Goergens <matthias.goergens@gmail.com>
Acked-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260923101749.3505886-1-matthias.goergens@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

0 files changed, 0 insertions, 0 deletions