MAINTAINERS: Update pstore maintainers

Update pstore to better reflect reality of active contributors:

- Remove Anton and Colin (thank you for your help through the years!)
- Move Tony to Reviewer
- Add Guilherme as Reviewer
- Add mailing list
- Upgrade to Supported

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Acked-by: Colin Cross <ccross@android.com>
Link: https://lore.kernel.org/r/20221011200112.731334-6-keescook@chromium.org

Author: kees

MAINTAINERS

@@ -16641,10 +16641,10 @@ F:	net/psample
 
 PSTORE FILESYSTEM
 M:	Kees Cook <keescook@chromium.org>
-M:	Anton Vorontsov <anton@enomsg.org>
-M:	Colin Cross <ccross@android.com>
-M:	Tony Luck <tony.luck@intel.com>
-S:	Maintained
+R:	Tony Luck <tony.luck@intel.com>
+R:	Guilherme G. Piccoli <gpiccoli@igalia.com>
+L:	linux-hardening@vger.kernel.org
+S:	Supported
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/pstore
 F:	Documentation/admin-guide/ramoops.rst
 F:	Documentation/admin-guide/pstore-blk.rst