[gimp] po: adding app/dialogs/extensions-dialog.c in POTFILES.in.

[Jehan <jehanp src gnome org>]

commit de649f4d7af807538bc78969539198d27ed1b06a
Author: Jehan <jehan girinstud io>
Date:   Sat Jul 7 18:11:09 2018 +0200

    po: adding app/dialogs/extensions-dialog.c in POTFILES.in.
    
    Fixing the CI build!

 po/POTFILES.in | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 2ec3c471f3..ece0a50857 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -210,6 +210,7 @@ app/dialogs/convert-precision-dialog.c
 app/dialogs/data-delete-dialog.c
 app/dialogs/dialogs-constructors.c
 app/dialogs/dialogs.c
+app/dialogs/extensions-dialog.c
 app/dialogs/fade-dialog.c
 app/dialogs/file-open-dialog.c
 app/dialogs/file-open-location-dialog.c