Mark the package as side-effects free

[stof]

This helps Rollup and webpack when performing tree-shaking.

[koddsson]

Can you link to any documentation about this attribute? I can't find any on the rollup page or when searching the web for it.

[stof]

See https://webpack.js.org/guides/tree-shaking/#mark-the-file-as-side-effect-free for the webpack doc about it.
Rollup added support for this flag in their tree-shaking algorithm, but I don't think they have written documentation about it (other than a changelog line saying it is supported).

[koddsson]

Rollup added support for this flag in their tree-shaking algorithm, but I don't think they have written documentation about it (other than a changelog line saying it is supported).

Can you link to the changelog line? I Couldn't find it in the CHANGELOG.md or in any of the pull requests on rollup/rollup.

[stof]

@koddsson see the changelog for 5.0 in https://github.com/rollup/rollup-plugin-node-resolve/blob/master/CHANGELOG.md

[koddsson]

Hey @stof I appreciate the PR but we aren't using rollup or rollup-plugin-node-resolve in this project any more.