Bump lxml from 4.3.2 to 4.9.1

Bumps [lxml](https://github.com/lxml/lxml) from 4.3.2 to 4.9.1.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](lxml/lxml@lxml-4.3.2...lxml-4.9.1)

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

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

requirements.txt

@@ -15,7 +15,7 @@ greenlet==1.1.2 ; python_version  > '3.9'  # (Jammy)
 idna==2.8
 Jinja2==2.11.3 # min version = 2.10.1 (Focal - with security backports)
 libsass==0.18.0
-lxml==4.6.5 # min version = 4.5.0 (Focal - with security backports)
+lxml==4.9.1 # min version = 4.5.0 (Focal - with security backports)
 MarkupSafe==1.1.0
 num2words==0.5.6
 ofxparse==0.19; python_version <= '3.9'