docker: Increase caching; explicit serialization to force convergence.

docker: Adjust profile overrides

Signed-off-by: Jason Volk <jason@zemos.net>

docker/Dockerfile.kitchen

@@ -25,6 +25,7 @@ ${packages} \
 "
 
 RUN  \
+--mount=type=cache,dst=/var/lock/uwu/local,sharing=locked \
 --mount=type=cache,dst=${var_cache},sharing=locked \
 --mount=type=cache,dst=${var_lib_apt},sharing=locked \
 <<EOF