fix mixed content

Since the images are loaded on docker hub without going through a proxy like Github does the images were being loaded over http causing mixed content.

Author: OmgImAlexis

README.md

@@ -1,6 +1,6 @@
-![http://linuxserver.io](http://www.linuxserver.io/wp-content/uploads/2015/06/linuxserver_medium.png)
+![https://linuxserver.io](https://www.linuxserver.io/wp-content/uploads/2015/06/linuxserver_medium.png)
 
-The [LinuxServer.io](http://linuxserver.io) team brings you another quality container release featuring auto-update on startup, easy user mapping and community support. Be sure to checkout our [forums](http://forum.linuxserver.io) or for real-time support our [IRC](http://www.linuxserver.io/index.php/irc/) on freenode at `#linuxserver.io`.
+The [LinuxServer.io](https://linuxserver.io) team brings you another quality container release featuring auto-update on startup, easy user mapping and community support. Be sure to checkout our [forums](https://forum.linuxserver.io) or for real-time support our [IRC](https://www.linuxserver.io/index.php/irc/) on freenode at `#linuxserver.io`.
 
 # linuxserver/plex