systemd-boot: upgrade 246.2 -> 246.6

As systemd-boot shares SRCREV with the main systemd recipe, the version
should be kept in sync with it.

Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/meta/recipes-core/systemd/systemd-boot_246.2.bb b/meta/recipes-core/systemd/systemd-boot_246.6.bb
similarity index 100%
rename from meta/recipes-core/systemd/systemd-boot_246.2.bb
rename to meta/recipes-core/systemd/systemd-boot_246.6.bb