[gnome-tweak-tool] Consistently use /usr/bin/env python3 shebangs

[Patrick Griffis <pgriffis src gnome org>]

commit 969c0c81c13d5a8f0d25a074e8cae859ac022b97
Author: Patrick Griffis <tingping tingping se>
Date:   Fri Jun 9 13:57:38 2017 -0400

    Consistently use /usr/bin/env python3 shebangs
    
    This is just more flexible and supports more python installations.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=783531

 gnome-tweak-tool               |    2 +-
 gnome-tweak-tool-lid-inhibitor |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gnome-tweak-tool b/gnome-tweak-tool
index ff3461a..7c03bbf 100755
--- a/gnome-tweak-tool
+++ b/gnome-tweak-tool
@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/env python3
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/gnome-tweak-tool-lid-inhibitor b/gnome-tweak-tool-lid-inhibitor
index 8d67210..e8009bf 100755
--- a/gnome-tweak-tool-lid-inhibitor
+++ b/gnome-tweak-tool-lid-inhibitor
@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/env python3
 
 import gi
 gi.require_version("GLib", "2.0")