Update css-inline requirement from ==0.19.* to ==0.20.* (#5883)

Updates the requirements on [css-inline](https://github.com/Stranger6667/css-inline) to permit the latest version.
- [Release notes](https://github.com/Stranger6667/css-inline/releases)
- [Changelog](https://github.com/Stranger6667/css-inline/blob/master/CHANGELOG.md)
- [Commits](https://github.com/Stranger6667/css-inline/compare/c-v0.19.0...c-v0.20.0)

---
updated-dependencies:
- dependency-name: css-inline
  dependency-version: 0.20.0
  dependency-type: direct:production
...

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

pyproject.toml

@@ -33,7 +33,7 @@ dependencies = [
   "celery==5.6.*",
   "chardet==5.2.*",
   "cryptography>=44.0.0",
-  "css-inline==0.19.*",
+  "css-inline==0.20.*",
   "defusedcsv>=1.1.0",
   "dnspython==2.*",
   "Django[argon2]==4.2.*,>=4.2.26",