Merge pull request #794 from nexB/dependabot/pip/lxml-4.9.1

Bump lxml from 4.8.0 to 4.9.1

Author: TG1999

requirements.txt

@@ -48,7 +48,7 @@ jedi==0.18.1
 Jinja2==3.1.1
 jsonschema==3.2.0
 license-expression==21.6.14
-lxml==4.8.0
+lxml==4.9.1
 Markdown==3.3.4
 MarkupSafe==2.1.1
 matplotlib-inline==0.1.3