[gnome-builder/gnome-builder-3-28] Update POTFILES.skip

[Piotr Drąg <piotrdrag src gnome org>]

commit 58f6a57c261a18be37242ec23e28cbd498ccbcb2
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Wed Jun 13 16:41:08 2018 +0200

    Update POTFILES.skip

 po/POTFILES.skip | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/po/POTFILES.skip b/po/POTFILES.skip
index 53798dd96..77bfe536f 100644
--- a/po/POTFILES.skip
+++ b/po/POTFILES.skip
@@ -10,3 +10,4 @@ src/plugins/vala-pack/ide-vala-preferences-addin.c
 # though master does not.
 # https://bugzilla.gnome.org/show_bug.cgi?id=695008#c7
 submodules
+subprojects