Slow SASS watch scripts

[azerella]

Feature Request

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As found by @sukhrajghuman it appears that when testing things locally, the sass watch scripts are very slow.

For example with the core component, the watch script watch:sass: https://github.com/govau/design-system-components/blob/master/packages/core/package.json#L35 runs the entire build script which also bundles the js. We want to update the watch and build scripts to be more isolated.

This issue also involve updating the developer docs:
https://designsystem.gov.au/get-started/development-environment/

[azerella]

After a bit of digging it seems that in order to solve this easily we need to update the following scripts for each component.

design-system-components/packages/buttons/package.json

Line 35 in 1993bdc

"watch:sass": "onchange \"src/sass/*.scss\" \"tests/site/test.scss\" -- npm run build",

by swapping build -> build:js which will compile the sass quicker than the entire build script. This isn't ideal, we need to look at refactoring the helper.js properly at a later time. For now though, this should help a little: #626

[azerella]

I think we will icebox this until we are ready to split up and refactor the helper.js script that handles our build process. We can't achieve this issue easily without refactoring said script.