[libxslt] Change libxml2 Python config

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 4bc852bc2228f5dcf7b77cd4f8fd6adf4e507822
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Fri Apr 1 12:38:36 2022 +0200

    Change libxml2 Python config
    
    Fix CI build after AM_PATH_PYTHON change in libxml2.

 .gitlab-ci.yml | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 6d4d77f0..f33fd29d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -29,6 +29,7 @@ gcc:python3:
   only:
     - schedules
   variables:
+    PYTHON: "/usr/bin/python3"
     CONFIG: "--with-python=/usr/bin/python3"
     CFLAGS: "-O2"