Add a note about pnpm publish to publish command

[maticzav]

This PR adds a small note that changeset publish is going to use pnpm if it detects that the workspace uses pnpm package manager.

I had to check the code to verify that it does indeed correctly switch the package manager and thought other people might have the same problem just checking the docs.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 8eea9ba

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.

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