Fix grammar error (allows vs allow) (#6426)

Maxr1998 · fabaff · commit 0652a7b0a90d · 2018-10-02T10:44:01.000+02:00
diff --git a/source/_docs/mqtt/logging.markdown b/source/_docs/mqtt/logging.markdown
@@ -10,7 +10,7 @@ footer: true
 logo: mqtt.png
 ---
 
-The [logger](/components/logger/) component allow the logging of received MQTT messages.
+The [logger](/components/logger/) component allows the logging of received MQTT messages.
 
 ```yaml
 # Example configuration.yaml entry
