Only a versioned download URL is provided for v2

### Bug Description

google_sql_proxy (v1) could be downloaded from say https://dl.google.com/cloudsql/cloud_sql_proxy.linux.amd64 to grab the latest x64 Linux build. However, per the docs on https://cloud.google.com/sql/docs/postgres/connect-auth-proxy#linux-64-bit , only versioned download URLs are now published. Would it be possible to publish a "latest" URL that points at the latest release similar to what we had with v1? It would be great to reduce the number of manual upgrades we need to manage.

### Example code (or command)

```
// paste your code or command here
```

### Stacktrace

```bash

```

### Steps to reproduce?

1. Go to https://cloud.google.com/sql/docs/postgres/connect-auth-proxy#linux-64-bit
2. Try to programmatically download the latest version of the v2 proxy

### Environment

1. OS type and version: Linux x64, Windows x64, macOS (all archs)
2. Cloud SQL Proxy version (`./cloud-sql-proxy --version`): v2 all versions
3. Proxy invocation command (for example, `./cloud-sql-proxy --port 5432 INSTANCE_CONNECTION_NAME`): N/A

### Additional Details

_No response_