[foxy] Use master ros2.repos file (ros2#591)

This file will be the one updated regularly between now and the release.
We should update that this once we branch for Foxy.

Signed-off-by: Jacob Perron <[email protected]>

Author: jacobperron

source/Installation/Foxy/Linux-Development-Setup.rst

@@ -95,7 +95,7 @@ Create a workspace and clone all repos:
 
    mkdir -p ~/ros2_foxy/src
    cd ~/ros2_foxy
-   wget https://raw.githubusercontent.com/ros2/ros2/foxy/ros2.repos
+   wget https://raw.githubusercontent.com/ros2/ros2/master/ros2.repos
    vcs import src < ros2.repos
 
 Install dependencies using rosdep