Bump markdown2 from 2.3.8 to 2.4.0

Bumps [markdown2](https://github.com/trentm/python-markdown2) from 2.3.8 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@2.3.8...2.4.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -1,4 +1,4 @@
 pandas==1.0.3
 openpyxl==3.0.3
 jinja2==2.11.3
-markdown2==2.3.8
+markdown2==2.4.0