Update recipe/meta.yaml to be consistent with upstream

[wang-r-j]

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

Fix the requirements.
google/flax@7218915 google/flax#2406 google/flax#2407

@conda-forge-admin please rerender

[conda-forge-webservices]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[fabinsch]

Hi @PhilipVinc @avital @jheek @levskaya , I want to add xpag to conda-forge which relies on flax>=0.6.3. Currently, your feedstock is stuck at version 0.6.1 with several automatic PRs that failed when you released new versions, but it seems that merging this PR solves the problem. Thanks for your time and for having a look at it. Best, Fabian