build-appliance-image: update version to 15.0.0

Signed-off-by: Alexander Kanavin <alexander.kanavin@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/meta/recipes-core/images/build-appliance-image_14.0.0.bb b/meta/recipes-core/images/build-appliance-image_15.0.0.bb
similarity index 100%
rename from meta/recipes-core/images/build-appliance-image_14.0.0.bb
rename to meta/recipes-core/images/build-appliance-image_15.0.0.bb