Update readme to use libjpeg-dev dummy package

Resolves to libjpeg8 for pre-Jessie and libjpeg62-turbo for Jessie+

Readme.md

@@ -37,7 +37,7 @@ You can quickly install the dependencies by using the command for your OS:
 OS | Command
 ----- | -----
 OS X | Using [Homebrew](https://brew.sh/):<br/>`brew install pkg-config cairo pango libpng jpeg giflib`<br/><br/>Using [MacPorts](https://www.macports.org/):<br/>`port install pkgconfig cairo pango libpng jpeg giflib`
-Ubuntu | `sudo apt-get install libcairo2-dev libjpeg8-dev libpango1.0-dev libgif-dev build-essential g++`
+Ubuntu | `sudo apt-get install libcairo2-dev libjpeg-dev libpango1.0-dev libgif-dev build-essential g++`
 Fedora | `sudo yum install cairo cairo-devel cairomm-devel libjpeg-turbo-devel pango pango-devel pangomm pangomm-devel giflib-devel`
 Solaris | `pkgin install cairo pango pkg-config xproto renderproto kbproto xextproto`
 Windows | [Instructions on our wiki](https://github.com/Automattic/node-canvas/wiki/Installation---Windows)