Bump lxml from 4.6.3 to 4.6.5

Bumps [lxml](https://github.com/lxml/lxml) from 4.6.3 to 4.6.5.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](lxml/lxml@lxml-4.6.3...lxml-4.6.5)

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

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

requirements.txt

@@ -23,7 +23,7 @@ gunicorn==19.9.0
 idna==2.8
 importlib-metadata==1.6.0
 kombu==5.1.0
-lxml==4.6.3
+lxml==4.6.5
 numpy==1.18.1
 oauthlib==3.1.0
 pandas==0.25.3