chore(deps): bump markdown2 from 2.3.7 to 2.4.0

Bumps [markdown2](https://github.com/trentm/python-markdown2) from 2.3.7 to 2.4.0.
- [Release notes](https://github.com/trentm/python-markdown2/releases)
- [Changelog](https://github.com/trentm/python-markdown2/blob/master/CHANGES.md)
- [Commits](trentm/python-markdown2@2.3.7...2.4.0)

---
updated-dependencies:
- dependency-name: markdown2
  dependency-type: direct:production
...

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

requirements.txt

@@ -30,7 +30,7 @@ itypes==1.1.0
 Jinja2==2.10
 lazy-object-proxy==1.3.1
 lxml==4.3.2
-markdown2==2.3.7
+markdown2==2.4.0
 MarkupSafe==1.1.1
 mccabe==0.6.1
 mock==2.0.0