Add sideEffects: false to package.json

[pnavarrc]

Part of https://github.com/act-now-coalition/act-now-packages/issues/537 - Enabling tree shaking for @actnowcoalition/ui-components

The package is free of side effects (as far as I know), not sure why this is the only package where we don't have this flag. I'm going to also add "type": "module" on a follow up PR (just want to test the changes one by one).

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: e1ea8e51acd0a3cab2be44d237d1a9c7e7e5d742

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | ------------------------------ | ----- | | @actnowcoalition/ui-components | Patch |

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions[bot]]

Visit the preview URL for this PR (updated for commit e1ea8e5):

https://act-now-packages--pr543-pablo-ui-components-0deeltn8.web.app

_{(expires Thu, 19 Jan 2023 23:51:44 GMT)}

_{🔥 via Firebase Hosting GitHub Action 🌎}

_{Sign: ad39b6c29b2ae4e8fa7983fbf3316d2e514cb069}