MAINTAINERS: git://github.com -> https://github.com for nilfs2

Github deprecated the git:// links about a year ago, so let's move to the
https:// URLs instead.

Link: https://lkml.kernel.org/r/[e-mail]
Link: https://github.blog/2021-09-01-improving-git-protocol-security-github/
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Palmer Dabbelt <[e-mail]>
Signed-off-by: Ryusuke Konishi <[e-mail]>
Reported-by: Conor Dooley <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

MAINTAINERS

···
 S:	Supported
 W:	https://nilfs.sourceforge.io/
 W:	https://nilfs.osdn.jp/
-T:	git git://github.com/konis/nilfs2.git
+T:	git https://github.com/konis/nilfs2.git
 F:	Documentation/filesystems/nilfs2.rst
 F:	fs/nilfs2/
 F:	include/trace/events/nilfs2.h