layers/meta-resin: Update to version v2.15.1
layers/meta-resin: Update to version v2.15.1

Changelog-entry: Update the meta-resin submodule to version v2.15.1
Signed-off-by: Florin Sarbu <3a837a37a2ac9072a088641ec330e0e5d5b86f4e@resin.io>

resin-os/resin-artik