fix range for Markupsafe

[ivan2angelov]

https://markupsafe.palletsprojects.com/en/2.1.x/changes/
"Remove soft_unicode, which was previously deprecated. Use soft_str instead. #261"

• fixes #

Checklist:

• Add tests that demonstrate the correct behavior of the change. Tests should fail without the change.
• Add or update relevant docs, in the docs folder and in code.
• Add an entry in CHANGES.rst summarizing the change and linking to the issue.
• Add .. versionchanged:: entries in any relevant code docs.
• Run pre-commit hooks and fix any issues.
• Run pytest and tox, no tests failed.

[PhotoTeeborChoka]

Fix #1587 , highly appreciated as it fixes the break of current deployments due to MarkupSafe latest update - it no longer has compatible API.

[ThiefMaster]

Besides the fact that we always recommend pinning transitive dependencies, this change isn't correct. You're pinning the version in the latest development version which works perfectly fine with 2.1...

[davidism]

You are using an unsupported version of the project, please update to the latest version. Additionally, please read https://hynek.me/articles/semver-will-not-save-you/, then use a tool like pip-tools to pin your dependencies and control when you get updates. Be sure to run your tests with deprecation warnings treated as errors so that you get notified of these types of changes early.