Fix a webpack devtool that works without unsave-eval CSP

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

webpack.dev.js

@@ -8,5 +8,5 @@ module.exports = merge(common, {
 		noInfo: true,
 		overlay: true
 	},
-	devtool: '#eval-source-map',
+	devtool: 'source-map',
 })