Update svelte tooling

Author: zerodevx

rollup.config.js

@@ -3,6 +3,7 @@ import resolve from '@rollup/plugin-node-resolve'
 import commonjs from '@rollup/plugin-commonjs'
 import livereload from 'rollup-plugin-livereload'
 import { terser } from 'rollup-plugin-terser'
+import css from 'rollup-plugin-css-only'
 
 const production = !process.env.ROLLUP_WATCH
 
@@ -37,15 +38,18 @@ export default {
   },
   plugins: [
     svelte({
-      // enable run-time checks when not in production
-      dev: !production,
-      // we'll extract any component CSS out into
-      // a separate file - better for performance
-      css: css => {
-        css.write('bundle.css')
-      }
+      compilerOptions: {
+        // enable run-time checks when not in production
+        dev: !production,
+        css: false
+      },
+      emitCss: true
     }),
 
+    // we'll extract any component CSS out into
+    // a separate file - better for performance
+    css({ output: 'bundle.css' }),
+
     // If you have external dependencies installed from
     // npm, you'll most likely need these plugins. In
     // some cases you'll need additional configuration -