build(deps-dev): bump check-manifest from 0.37 to 0.40

Bumps [check-manifest](https://github.com/mgedmin/check-manifest) from 0.37 to 0.40.
- [Release notes](https://github.com/mgedmin/check-manifest/releases)
- [Changelog](https://github.com/mgedmin/check-manifest/blob/master/CHANGES.rst)
- [Commits](mgedmin/check-manifest@0.37...0.40)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

requirements/dev.txt

@@ -1,5 +1,5 @@
 Sphinx==1.8.3
-check-manifest==0.37
+check-manifest==0.40
 cogapp
 flake8==3.7.9
 hg+https://nicfit@bitbucket.org/nicfit/sphinxcontrib-bitbucket