chore(deps): update rollup to v1.31.1

[thi-bot]

This PR contains the following updates:

Package	Update	Type	Change	Sourcegraph
rollup	patch	devDependencies	1.31.0 -> 1.31.1

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Release Notes

rollup/rollup

### [`v1.31.1`](https://togithub.com/rollup/rollup/blob/master/CHANGELOG.md#​1311) [Compare Source](https://togithub.com/rollup/rollup/compare/v1.31.0...v1.31.1) _2020-02-14_ ##### Bug Fixes - Make sure errored files are always re-evaluated in watch mode to avoid an issue in the typescript plugin ([#​3388](https://togithub.com/rollup/rollup/issues/3388)) ##### Pull Requests - [#​3366](https://togithub.com/rollup/rollup/pull/3366): Correct spelling minifaction to minification ([@​VictorHom](https://togithub.com/VictorHom)) - [#​3371](https://togithub.com/rollup/rollup/pull/3371): Adjust bug template to mention REPL.it ([@​lukastaegert](https://togithub.com/lukastaegert)) - [#​3388](https://togithub.com/rollup/rollup/pull/3388): Run transform hooks again in watch mode on files that errored ([@​lukastaegert](https://togithub.com/lukastaegert))

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