[pygobject] setup.py: fix distcheck

[Christoph Reiter <creiter src gnome org>]

commit 1138bc7e0aeb8d4e7354c6cfd5a63edaa724d3fb
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Tue Feb 27 12:46:11 2018 +0100

    setup.py: fix distcheck

 MANIFEST.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/MANIFEST.in b/MANIFEST.in
index e8aeecbb..bddf19a6 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -16,4 +16,4 @@ recursive-include gi *.am *.h
 recursive-include pygtkcompat *.am
 recursive-include tests *.py *.c *.h *.xml *.supp *.am
 recursive-include docs *.rst *.svg LICENSE *.ico *.png *.css *.py *.dia Makefile
-recursive-include .gitlab-ci *.sh *.rst Dockerfile
+recursive-include .gitlab-ci *.sh *.rst *.py Dockerfile