Updated regex for message plugin

This regex will match on
s
s foo
slack foo

aprsd_slack_plugin/message_plugin.py

@@ -46,7 +46,7 @@ class SlackMessagePlugin(base_plugin.SlackPluginBase):
     version = aprsd_slack_plugin.__version__
 
     # matches any string starting with h or H
-    command_regex = "^[sS]"
+    command_regex = r"^([s]|[s]\s|slack)"
     command_name = "message-slack"
 
     def setup(self):

aprsd_slack_plugin/notify_plugin.py

@@ -1,6 +1,6 @@
 import logging
 
-from aprsd import messaging, packets, plugin
+from aprsd import packets, plugin
 from oslo_config import cfg
 
 import aprsd_slack_plugin
@@ -53,4 +53,4 @@ class SlackNotifyPlugin(
                 self.swc.chat_postMessage(**message)
 
         # Don't have aprsd try and send a reply
-        return messaging.NULL_MESSAGE
+        return packets.NULL_MESSAGE