Update lxml requirement from <5,>=4.5.0 to >=4.5.0,<6 (#163)

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-4.5.0...lxml-5.0.0)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -10,4 +10,4 @@
 beautifulsoup4 >=4.9.0,<5
 fast_diff_match_patch >=2.0.1,<3
 html5-parser >=0.4.0,<0.5 --no-binary lxml
-lxml >=4.5.0,<5
+lxml >=4.5.0,<6