Bump gunicorn from 20.0.2 to 20.0.3 (#1143)

Bumps [gunicorn](https://github.com/benoitc/gunicorn) from 20.0.2 to 20.0.3.
- [Release notes](https://github.com/benoitc/gunicorn/releases)
- [Commits](https://github.com/benoitc/gunicorn/compare/20.0.2...20.0.3)

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

http_service/requirements.txt

@@ -4,7 +4,7 @@ cerberus==1.3.2
 Flask==1.1.1
 flask-apispec==0.8.3
 flask-cors==3.0.8
-gunicorn==20.0.2
+gunicorn==20.0.3
 marshmallow==3.2.2
 rq==1.1.0
 rq-dashboard==0.6.0