[gtksourceview] Update POTFILES.skip

[Piotr Drąg <piotrdrag src gnome org>]

commit 533406aa4ebc9e6b8544e598dff7f08ebbe27b8a
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Fri Feb 14 17:05:30 2020 +0100

    Update POTFILES.skip

 po/POTFILES.skip | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/po/POTFILES.skip b/po/POTFILES.skip
index 43884c09..b1a71dbe 100644
--- a/po/POTFILES.skip
+++ b/po/POTFILES.skip
@@ -22,6 +22,7 @@ data/language-specs/chdr.lang
 data/language-specs/c.lang
 data/language-specs/cmake.lang
 data/language-specs/cobol.lang
+data/language-specs/commonlisp.lang
 data/language-specs/cpphdr.lang
 data/language-specs/cpp.lang
 data/language-specs/csharp.lang