chore(deps): update dependency rollup to ^2.31.0

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
rollup (source)	devDependencies	minor	^2.30.0 -> ^2.31.0

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Release Notes

rollup/rollup

### [`v2.31.0`](https://togithub.com/rollup/rollup/blob/master/CHANGELOG.md#​2310) [Compare Source](https://togithub.com/rollup/rollup/compare/v2.30.0...v2.31.0) _2020-10-15_ ##### Features - When using the `output.moduleToStringTag` option, also add the tag to entries with exports and simulated external namespaces ([#​3822](https://togithub.com/rollup/rollup/issues/3822)) - Add the `__esModule` interop marker to IIFE global variables unless `output.esModule` is turned off ([#​3822](https://togithub.com/rollup/rollup/issues/3822)) ##### Pull Requests - [#​3822](https://togithub.com/rollup/rollup/pull/3822): Add module toStringTag to entries and interop namespaces ([@​lukastaegert](https://togithub.com/lukastaegert))

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