fix(parse): coerce version prerelease type to string (#184)

This PR fixes a type error.

```shell
TypeError: parsedVersion?.prerelease[0]?.endsWith is not a function
 ❯ parse node_modules/nw/src/parse.js:49:39
 ❯ Module.findpath node_modules/nw/src/util.js:51:15
```

src/parse.js

@@ -46,7 +46,7 @@ export default async function parse(options) {
         parsedVersion.patch
     ].join('.');
     options.flavor = options.flavor || process.env.npm_config_nwjs_build_type || process.env.NWJS_BUILD_TYPE || 'normal';
-    if (parsedVersion?.prerelease[0]?.endsWith('sdk')) {
+    if (String(parsedVersion?.prerelease[0]).endsWith('sdk')) {
         options.flavor = 'sdk';
     }
     options.platform = options.platform || util.PLATFORM_KV[process.env.npm_config_nwjs_platform || process.env.NWJS_PLATFORM || process.platform];

test/findpath.test.js

@@ -1,13 +1,8 @@
-import fs from 'node:fs';
 import { expect, test } from 'vitest';
 
 import util from '../src/util.js';
 
-test('nwjs has downloaded and been extracted', function () {
-  util.findpath('nwjs', { flavor: 'sdk' }).then(function (path) {
-    expect(fs.existsSync(path)).toEqual(true);
-  })
-    .catch((error) => {
-      console.log(error);
-    });
+test('nwjs has downloaded and been extracted', async function () {
+  const path = await util.findpath('nwjs', { flavor: 'sdk' });
+  expect(util.fileExists(path)).resolves.toEqual(true);
 });