[copp] bind copp-config.service to sonic.target (#8969)

copp-config service needs to be started after sonic.target so that it could
render the copp-config with the latest information.

It also needs to be restarted when config reload or load_minigraph is invoked.

Signed-off-by: Ying Xie <ying.xie@microsoft.com>

files/image_config/copp/copp-config.service

@@ -2,10 +2,12 @@
 Description=Update CoPP configuration
 Requires=updategraph.service
 After=updategraph.service
+BindsTo=sonic.target
+After=sonic.target
 
 [Service]
 Type=oneshot
 ExecStart=/usr/bin/copp-config.sh
 
 [Install]
-WantedBy=multi-user.target
+WantedBy=sonic.target