Add publish plugin to registry (#2835)

Update registry.json

Author: infinitepower18

plugins/registry.json

@@ -222,5 +222,14 @@
         "title": "Slow Mode",
         "icon_url": "https://cdn.discordapp.com/attachments/717029057635549274/717033838966210601/Slow_mode_-_icon.png",
         "thumbnail_url": "https://cdn.discordapp.com/attachments/717029057635549274/717029110907666482/Slow_mode_plugin_-_thumbnail.png"
+    },
+       "publish": {
+        "repository": "codeinteger6/modmail-plugins",
+        "branch": "master",
+        "description": "Publish messages sent in announcement channels.",
+        "bot_version": "3.5.0",
+        "title": "Publish",
+        "icon_url": "https://user-images.githubusercontent.com/44692189/89184422-96de3600-d5ba-11ea-98ea-d096aa385ad5.png",
+        "thumbnail_url": "https://user-images.githubusercontent.com/44692189/89184422-96de3600-d5ba-11ea-98ea-d096aa385ad5.png"
     }
 }