[ghex] docs: Fix libgtkhex versioning in gi-docgen docs

[Logan Rathbone <larathbone src gnome org>]

commit 5bc1629a2a77dcf21cb2e8e62cc9a4395dbc3a66
Author: Logan Rathbone <poprocks gmail com>
Date:   Mon Apr 4 23:15:30 2022 -0400

    docs: Fix libgtkhex versioning in gi-docgen docs

 docs/meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/docs/meson.build b/docs/meson.build
index ae7a51f..2b65cd3 100644
--- a/docs/meson.build
+++ b/docs/meson.build
@@ -3,7 +3,7 @@ if build_gtk_doc and not get_option('introspection').allowed()
 endif
 
 toml_conf = configuration_data()
-toml_conf.set('version', meson.project_version())
+toml_conf.set('version', libgtkhex_version)
 
 gidocgen = find_program('gi-docgen', required: get_option('gtk_doc'))
 gir_apiname = 'gtkhex-@0@.0'.format(libgtkhex_api_version)