Ensure installation directory exists before downloading binary

- Updated the `download` method in `Binary` class to be asynchronous.
- Added a check to ensure the `installDir` directory exists before starting the download.
- If the directory does not exist, it is created with `fs.mkdir` using the `recursive` option.

npm/src/index.ts

@@ -72,7 +72,12 @@ export class Binary {
     return join(this.installDir, this.name);
   }
 
-  download(url: URL): Promise<void> {
+  async download(url: URL): Promise<void> {
+    // Ensure the install directory exists
+    if (!await fileExists(this.installDir)) {
+      await fs.mkdir(this.installDir, { recursive: true });
+    }
+
     return pipeline(
       got.stream(url),
       new stream.PassThrough(),