Add semicolon at the end of UMD build (#129)

Allows for safe script concatenation; see Tampermonkey/tampermonkey#595

scripts/buildUMD.ts

@@ -32,7 +32,7 @@ minify(src, opts).then(async out => {
   const res = "!function(f){typeof module!='undefined'&&typeof exports=='object'?module.exports=f():typeof define!='undefined'&&define.amd?define(f):(typeof self!='undefined'?self:this).fflate=f()}(function(){var _e={};" +
     out.code!.replace(/exports\.(.*) = void 0;\n/, '').replace(/exports\./g, '_e.').replace(/require\("\.\/node-worker\.cjs"\)/,
     "(typeof module!='undefined'&&typeof exports=='object'?function(_f){" + nodeWkrOut + 'return _f}:function(_f){' + wkrOut + 'return _f})({})'
-  ) + 'return _e})';
+  ) + 'return _e});';
   if (!existsSync(p('umd'))) mkdirSync(p('umd'));
   writeFileSync(p('umd', 'index.js'), res);
 });