Bump lxml from 4.5.1 to 4.5.2

Bumps [lxml](https://github.com/lxml/lxml) from 4.5.1 to 4.5.2.
- [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>

requirements.txt

@@ -3,7 +3,7 @@ chardet==3.0.4
 idna==2.10
 Jinja2==2.11.2
 kinto-http==10.7.0
-lxml==4.5.1
+lxml==4.5.2
 MarkupSafe==1.1.1
 python-dateutil==2.8.1
 requests==2.24.0