fix hmr : invalidate css files

[franck-co]

fixes #11

In 5785cc8 the handleHotUpdate hook was removed.

// Re-parse .css.ts files when they change
async handleHotUpdate({file, modules}) {
	if (!cssFileFilter.test(file)) return
	try {
		const virtuals: any[] = []
		const invalidate = (type: string) => {
			const found = server.moduleGraph.getModulesByFile(`${file}${type}`)
			found?.forEach(m => {
				virtuals.push(m)
				return server.moduleGraph.invalidateModule(m)
			})
		}
		invalidate(virtualExtCss)
		invalidate(virtualExtJs)
		// load new CSS
		await server.ssrLoadModule(file)
		return [...modules, ...virtuals]
	} catch (e) {
		// eslint-disable-next-line no-console
		console.error(e)
		throw e
	}
}

It was responsible of invalidating .vanilla.css files.
Therefore it was required to do a full restart of the vite dev server to see style updates.

This PR reintroduce the invalidation of .vanilla.css files in the transform hook
to fix the HMR.

[wmertens]

Awesome, thanks!

[brandonpittman]

Has this been released?