docs: Update CONTRIBUTING.md

[alexfertel]

Removed this, since it is no longer the case.

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PR-Codex overview

This PR focuses on updating the CONTRIBUTING.md file to provide instructions on creating changesets and marking changes as minor/patch releases.

Detailed summary

• Added instructions for creating changesets using pnpm changeset
• Advised using bold text instead of headings for section headings in changesets
• Provided guidance on updating existing changesets in PRs

✨ Ask PR-Codex anything about this PR by commenting with /codex {your question}

[changeset-bot]

⚠️ No Changeset found

Latest commit: 43c3b5d

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[vercel]

@alexfertel is attempting to deploy a commit to the wagmi Team on Vercel.

A member of the Team first needs to authorize it.