Update python3-gtk as well

Updating everything else broke GTK.

Change-Id: I2e810f307bc077f7f44ed227b5def7c92e75824f
diff --git a/WORKSPACE b/WORKSPACE
index 210a7f0..e7de0e2 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -447,8 +447,8 @@
 http_archive(
     name = "python_gtk",
     build_file = "@//debian:python_gtk.BUILD",
-    sha256 = "2c95dbce3ead87ad7d64327535f08c95ab14d5c12d5646530d734e70a1921130",
-    url = "https://www.frc971.org/Build-Dependencies/python_gtk-2.tar.gz",
+    sha256 = "d8310f3a8b8bd7d7b0040bfec4bb7818ab6221031ffd334525de3618585148b8",
+    url = "https://www.frc971.org/Build-Dependencies/python_gtk-3.tar.gz",
 )
 
 # Downloaded from