Update Dockerfile_promtail

Signed-off-by: abhishek-sa1 <abhishek.sa3@dell.com>

control_plane/roles/control_plane_monitoring/files/Dockerfile_promtail

@@ -1 +1,3 @@
+FROM docker.io/grafana/promtail:2.4.1
 
+COPY promtail_config.yml /etc/promtail/config.yml