Bump lxml from 4.1.1 to 4.6.3

Bumps [lxml](https://github.com/lxml/lxml) from 4.1.1 to 4.6.3.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](lxml/lxml@lxml-4.1.1...lxml-4.6.3)

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

Author: dependabot[bot]

requirements.txt

@@ -1,4 +1,4 @@
 cssselect==1.0.1
-lxml==4.1.1
+lxml==4.6.3
 reppy==0.4.12
 requests==2.21