[gtksourceview/gtksourceview-4-8] Update POTFILES.skip

[Piotr Drąg <piotrdrag src gnome org>]

commit 85097228088a8f39e3a209c1290200d35c1c9533
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Sat Sep 18 12:17:35 2021 +0200

    Update POTFILES.skip

 po/POTFILES.skip | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/po/POTFILES.skip b/po/POTFILES.skip
index bec016ec..1017607d 100644
--- a/po/POTFILES.skip
+++ b/po/POTFILES.skip
@@ -87,6 +87,7 @@ data/language-specs/jsx.lang
 data/language-specs/julia.lang
 data/language-specs/kotlin.lang
 data/language-specs/latex.lang
+data/language-specs/lean.lang
 data/language-specs/less.lang
 data/language-specs/lex.lang
 data/language-specs/libtool.lang