add documentation about changing and removing icons (#62)

docs/icons.md

@@ -18,8 +18,18 @@ Transforms the icon to an XCode Image Set
 
 ## Synchronising icons
 
-- Create the icon and add it to the Figma icon library https://www.figma.com/file/gkNXqPoiJhEv2wt0EJpew4/Compound-Icons?type=design&mode=design&t=lYEYAWjnNUSGFhV4-11
+- Create the icon and add it to the [Figma icon library](https://www.figma.com/file/gkNXqPoiJhEv2wt0EJpew4/Compound-Icons?type=design&mode=design&t=lYEYAWjnNUSGFhV4-11)
+  . Refer to [the guidelines for icon preparation](https://www.figma.com/file/gkNXqPoiJhEv2wt0EJpew4/Compound-Icons?type=design&node-id=280-6047&mode=design&t=wOCsc1FBoOz4YnJo-0).
 - Use [SVG Export](https://www.figma.com/community/plugin/814345141907543603) on Figma. Making sure to use `currentColor` so the icon can be tintable
 - Copy the icons to the `icons/` folder
 - Run `yarn build` at the root of the project or ask a maintainer to do this for you
 - Open a pull request against the `develop` branch
+
+## Removing or changing icons
+
+Removing an icon is a breaking change, and should be reflected in the changelog and a major change in package version.
+
+Renaming an icon is functionally the same as deleting an icon and adding another. This should be marked as a breaking
+change. The changelog should include migration instructions.
+
+Visual changes to icons are considered a backwards compatible change (semver [patch](https://semver.org/)).