Purpose

Fix link on PyPI.

Rationale

On the PyPI page, the "changelog" link pointed to a 404 because it assumed Markdown instead of reSTructred text.

How did you test?

I can't really, this need to be published on PyPI.

How to Verify

1. After merging this, publish a release.
2. Navigate to https://pypi.org/project/python-semantic-release/
3. In the sidebar on the left, click "changelog"

Expected result: Shows changelog instead of 404.

PR Completion Checklist

• Reviewed & followed the Contributor Guidelines

• Changes Implemented & Validation pipeline succeeds ❌ Can't, see comment above.

• Commits follow the Conventional Commits standard
  and are separated into the proper commit type and scope (recommended order: test, build, feat/fix, docs)

• Appropriate Unit tests added/updated ❌ n/a

• Appropriate End-to-End tests added/updated ❌ n/a

• Appropriate Documentation added/updated and syntax validated for sphinx build (see Contributor Guidelines) ❌ It's a docs fix.