Bump lxml from 3.5 to 4.6.5

Bumps [lxml](https://github.com/lxml/lxml) from 3.5 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-3.5.0...lxml-4.6.5)

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 beautifulsoup4==4.4.1
 Markdown
 html2text==2014.12.29
-lxml==3.5
+lxml==4.6.5
 parse==1.8.2
 aiohttp==3.1.3