[gi-docgen] build: Use setuptools instead of distutils

[Emmanuele Bassi <ebassi src gnome org>]

commit c0458ac758cdf8945a4bca01dec6b72a20b002a4
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Sat Feb 12 17:59:36 2022 +0000

    build: Use setuptools instead of distutils
    
    The distutils module has been deprecated, and will be
    removed in a future version of Python.

 setup.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/setup.py b/setup.py
index 9a38aa6..e38ae79 100644
--- a/setup.py
+++ b/setup.py
@@ -8,7 +8,7 @@ if sys.version_info < (3, 6, 0):
 
 from gidocgen.core import version
 
-from distutils.command.build_py import build_py as _build_py
+from setuptools.command.build_py import build_py as _build_py
 from setuptools import setup