Update lxml requirement from ~=4.5.1 to ~=4.5.2 (#609)

Updates the requirements on [lxml](https://github.com/lxml/lxml) to permit the latest version.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](lxml/lxml@lxml-4.5.1...lxml-4.5.2)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

requirements.txt

@@ -6,7 +6,7 @@ docopt ~=0.6.2
 git+https://github.com/anastasia/htmldiffer@develop
 git+https://github.com/danielballan/htmltreediff@customize
 html5-parser ~=0.4.9 --no-binary lxml
-lxml ~=4.5.1
+lxml ~=4.5.2
 sentry-sdk ~=0.15.1
 requests ~=2.24.0
 toolz ~=0.10.0