[pitivi] Update POTFILES.in

[Piotr Drąg <piotrdrag src gnome org>]

commit e0255d3daeaf2b1483eb459ee7256b97400c3e80
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Fri Sep 27 19:39:55 2019 +0200

    Update POTFILES.in

 po/POTFILES.in | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 49d32d65..46e73caf 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -55,6 +55,7 @@ pitivi/dialogs/missingasset.py
 pitivi/dialogs/prefs.py
 
 pitivi/utils/misc.py
+pitivi/utils/proxy.py
 pitivi/utils/ui.py
 pitivi/utils/widgets.py