new: pkg: add name of builder at the beginning of the build

.drone.yml

@@ -18,6 +18,8 @@ steps:
       ## final build docker repository access.
       docker_config_json: {from_secret: DOCKER_CONFIG_JSON}
     commands:
+      - |
+        echo "BUILDING ON: ${DRONE_SYSTEM_HOSTNAME}"
       - |
         mkdir -p /root/.ssh
         cat <<EOF > /root/.ssh/config