Bump bellybutton from 0.3.0 to 0.3.1

Bumps [bellybutton](https://github.com/hchasestevens/bellybutton) from 0.3.0 to 0.3.1.
- [Release notes](https://github.com/hchasestevens/bellybutton/releases)
- [Commits](https://github.com/hchasestevens/bellybutton/commits)

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

requirements.txt

@@ -5,7 +5,7 @@ aresponses==2.0.0
 asynctest==0.13.0
 attrs==20.3.0
 backoff==1.10.0
-bellybutton==0.3.0
+bellybutton==0.3.1
 colorlog==4.6.2
 fnvhash>=0.1.0<1.0.0
 hacs_frontend==202012051441