Add bust cache parameter to mermaid iframe url

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🦋 Changeset detected

Latest commit: 14c56dfcdc9287abc49fd2d96a68db9eaface584

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | ---------------------------- | ----- | | @gitbook/integration-mermaid | Patch |

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