BLD: unpin jinja, satiate dependabot

[tangkong]

Description

Unpin jinja, dependabot keeps sending me emails

Motivation and Context

leave my inbox alone

How Has This Been Tested?

Let's see if the previously stated incompatibility with sphinx is still an issue

Where Has This Been Documented?

This PR

Pre-merge checklist

• Code works interactively
• Code contains descriptive docstrings, including context and API
• New/changed functions and methods are covered in the test suite where possible
• Code has been checked for threading issues (no blocking tasks in GUI thread)
• Test suite passes locally
• Test suite passes on GitHub Actions
• Ran docs/pre-release-notes.sh and created a pre-release documentation page
• Pre-release docs include context, functional descriptions, and contributors as appropriate