Update dependency rollup to v3.21.0

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
rollup (source)	3.20.7 -> 3.21.0

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Release Notes

rollup/rollup

### [`v3.21.0`](https://togithub.com/rollup/rollup/blob/HEAD/CHANGELOG.md#​3210) [Compare Source](https://togithub.com/rollup/rollup/compare/v3.20.7...v3.21.0) *2023-04-23* ##### Features - Support tree-shaking of named exports in dynamic imports when using destructuring and similar patterns ([#​4952](https://togithub.com/rollup/rollup/issues/4952)) ##### Pull Requests - [#​4952](https://togithub.com/rollup/rollup/pull/4952): feat: tree-shake deterministic dynamic imports ([@​antfu](https://togithub.com/antfu))

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