chore(deps): update dependency rollup to v2.50.6

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
rollup (source)	2.50.5 -> 2.50.6

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Release Notes

rollup/rollup

### [`v2.50.6`](https://togithub.com/rollup/rollup/blob/master/CHANGELOG.md#​2506) [Compare Source](https://togithub.com/rollup/rollup/compare/v2.50.5...v2.50.6) *2021-06-03* ##### Bug Fixes - Do not consider the object spread operator as side effect when `propertyReadSideEffects` are false ([#​4119](https://togithub.com/rollup/rollup/issues/4119)) - Detect side effects when returning thenables from async arrow functions ([#​4120](https://togithub.com/rollup/rollup/issues/4120)) ##### Pull Requests - [#​4119](https://togithub.com/rollup/rollup/pull/4119): Respect propertyReadSideEffects in spread elements ([@​lukastaegert](https://togithub.com/lukastaegert)) - [#​4120](https://togithub.com/rollup/rollup/pull/4120): Detect async arrow thenable side effects ([@​lukastaegert](https://togithub.com/lukastaegert))

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