[gnome-builder] Update POTFILES.in

[Piotr Drąg <piotrdrag src gnome org>]

commit d8e23672ee967453fa13566871d7f0ca9508f331
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Fri Mar 1 19:52:30 2019 +0100

    Update POTFILES.in

 po/POTFILES.in | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 27ab5aec2..b50a45e1d 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -333,6 +333,7 @@ src/plugins/terminal/gbp-terminal-application-addin.c
 src/plugins/terminal/gbp-terminal-workspace-addin.c
 src/plugins/terminal/gtk/menus.ui
 src/plugins/testui/gbp-test-output-panel.c
+src/plugins/testui/gbp-test-output-panel.ui
 src/plugins/testui/gbp-test-tree-addin.c
 src/plugins/todo/gbp-todo-panel.c
 src/plugins/todo/gbp-todo-workspace-addin.c