Build: Fix npm run build-dev to support Rollup 4

Follows-up 3d8b99e. The module
changed upstream in Rollup 3.0 to use a named export instead.

Ref rollup/rollup@260bcf0ee4f.

build/watch.js

@@ -5,7 +5,7 @@ const path = require('path');
 const rollup = require('rollup');
 const kleur = require('kleur');
 const watch = require('node-watch');
-const loadConfigFile = require('rollup/dist/loadConfigFile.js');
+const { loadConfigFile } = require('rollup/dist/loadConfigFile.js');
 
 const { preprocess } = require('./dist-replace.js');