fix: polyfill 'fetch' for Node target

webpack.config.js

@@ -1,4 +1,5 @@
 const path = require('path');
+const {ProvidePlugin} = require('webpack');
 const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
 
 const base = {
@@ -64,6 +65,11 @@ module.exports = [
             'js-md5': true,
             'localforage': true,
             'text-encoding': true
-        }
+        },
+        plugins: [
+            new ProvidePlugin({
+                fetch: ['node-fetch', 'default']
+            })
+        ]
     })
 ];