Added Weaviate client to the requirements.txt file

[bobvanluijt]

Background

To use the Weaviate backend, people need to manually install the Python client. Added it to requirements.txt to fix this.

Changes

Added Weaviate to requirements.txt

Documentation

n.a.

Test Plan

Validated that the complete requirements.txt file is correct

PR Quality Checklist

• My pull request is atomic and focuses on a single change.
• I have thoroughly tested my changes with multiple different prompts.
• I have considered potential risks and mitigations for my changes.
• I have documented my changes clearly and comprehensively.
• I have not snuck in any "extra" small tweaks changes

[BillSchumacher]

If they want to use Weaviate they can install it separately. That's why we have try except ImportErrors on all memory backends.

[bobvanluijt]

That's why we have try except ImportErrors on all memory backends.

@BillSchumacher Aha, apologies; I wasn't aware this was a design choice.

Would you suggest adding it to the readme to avoid confusion? Or just let it throw the error?

[bobvanluijt]

Additionally, I noticed that some backends are in the requirements.txt file, hence the PR.