Bump lxml from 4.8.0 to 4.9.1

Bumps [lxml](https://github.com/lxml/lxml) from 4.8.0 to 4.9.1.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](https://github.com/lxml/lxml/compare/lxml-4.8.0...lxml-4.9.1)

---
updated-dependencies:
- dependency-name: lxml
  dependency-type: indirect
...

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

requirements.txt

@@ -89,8 +89,6 @@ humanize==4.1.0
     # via -r requirements.in
 idna==3.3
     # via requests
-importlib-metadata==4.11.4
-    # via flask
 itsdangerous==2.1.2
     # via
     #   -r requirements.in
@@ -111,7 +109,7 @@ lml==0.1.0
     # via
     #   pyexcel
     #   pyexcel-io
-lxml==4.8.0
+lxml==4.9.1
     # via
     #   pyexcel-ezodf
     #   pyexcel-ods3
@@ -215,8 +213,6 @@ statsd==3.3.0
     # via notifications-utils
 texttable==1.6.4
     # via pyexcel
-typing-extensions==4.2.0
-    # via pypdf2
 urllib3==1.26.9
     # via
     #   botocore
@@ -238,8 +234,6 @@ xlrd==2.0.1
     # via pyexcel-xls
 xlwt==1.3.0
     # via pyexcel-xls
-zipp==3.8.0
-    # via importlib-metadata
 
 # The following packages are considered to be unsafe in a requirements file:
 # setuptools