Correct section number in UPGRADING

KasperFranz · nikic · commit c4b77e03b1f4 · 2019-02-12T15:09:09.000+01:00
This make the top list follow the bottom numbering

[ci skip]
diff --git a/UPGRADING b/UPGRADING
@@ -12,7 +12,7 @@ PHP 7.4 UPGRADE NOTES
 10. New Global Constants
 11. Changes to INI File Handling
 12. Windows Support
-12. Migration to pkg-config
+13. Migration to pkg-config
 14. Other Changes
 15. Performance Improvements
 
