Added note about xenial-220 pointing to latest

Author: ffdixon

_posts/2019-02-15-install.md

@@ -360,6 +360,8 @@ Next, your server needs to know where to download the BigBlueButton 2.2 packages
 $ echo "deb https://ubuntu.bigbluebutton.org/xenial-220/ bigbluebutton-xenial main" | sudo tee /etc/apt/sources.list.d/bigbluebutton.list
 ```
 
+Note: The directory `xenial-220` points to the latest BigBlueButton 2.2.X packages.
+
 Next, run `apt-get` to pull down the links to the latest BigBlueButton packages.
 
 ```bash