feat: Use previous image as Docker cache

hooks/build

@@ -3,7 +3,10 @@
 # Docker Daemon Build Hook
 # $IMAGE_NAME var is injected into the build so the tag is correct.
 
+docker pull ${DOCKER_REPO}:latest
+
 docker build \
+        --cache-from=${DOCKER_REPO}:latest \
         --build-arg=BUILD_DATE="$(date +"%Y-%m-%d %H:%M:%S%:z")" \
 		--build-arg=VCS_REF="$(git rev-parse --short HEAD)" \
 		-t ${IMAGE_NAME} .