Update Dockerfile

Signed-off-by: Shubhangi-dell <shubhangi_srivastava@dell.com>

control_plane/roles/control_plane_device/files/Dockerfile

@@ -1,5 +1,5 @@
 # Dockerfile for creating the management network container
-FROM alpine:latest
+FROM alpine:docker_os
 
 #Installing packages
 RUN apk add dhcp