Update authors.yaml and regsitry.yaml url value in pull request template.

[taranjeet]

This fixes the URL of registry.yaml and authors.yaml in the pull request template.

Summary

This fixes the URL of registry.yaml and authors.yaml in the pull request template.
At present, the URL of the registry.yaml points to github.com/registry.yaml and authors.yaml point to github.com/authors.yaml.
This is because it's a relative path.

Motivation

These changes improve the contribution guidelines and help point a user to the correct files.

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For new content

When contributing new content, read through our contribution guidelines, and mark the following action items as completed:

• I have added a new entry in registry.yaml (and, optionally, in authors.yaml) so that my content renders on the cookbook website.
• I have conducted a self-review of my content based on the contribution guidelines:
  • Relevance: This content is related to building with OpenAI technologies and is useful to others.
  • Uniqueness: I have searched for related examples in the OpenAI Cookbook, and verified that my content offers new insights or unique information compared to existing documentation.
  • Spelling and Grammar: I have checked for spelling or grammatical mistakes.
  • Clarity: I have done a final read-through and verified that my submission is well-organized and easy to understand.
  • Correctness: The information I include is correct and all of my code executes successfully.
  • Completeness: I have explained everything fully, including all necessary references and citations.

We will rate each of these areas on a scale from 1 to 4, and will only accept contributions that score 3 or higher on all areas. Refer to our contribution guidelines for more details.

[simonpfish]

Thank you!