[retro-gtk] Update dependencies in README.md

[Adrien Plazas <aplazas src gnome org>]

commit 0b4d62612ece5b688fc6795a7b754189a0801bc9
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Fri Sep 9 09:22:30 2016 +0200

    Update dependencies in README.md

 README.md |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/README.md b/README.md
index b1dfd36..0c17d07 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,7 @@ retro-gtk depends on the following libraries at compile time and at run time:
 - gtk+-3.0
 - cairo
 - libpulse
+- libpulse-simple
 
 ## Compiling