How do I authenticate the Databricks SQL Driver for Go using the NewConnector function with a service principal's OAuth secret and environment variables?
To authenticate the Databricks SQL Driver for Go using the NewConnector function with a service principal's OAuth secret and environment variables, you first need to add the following import declaration:

```go
"github.com/databricks/databricks-sql-go/auth/oauth/m2m"
```

Then, use the following code snippet, assuming you have set the required environment variables:

```go
authenticator := m2m.NewAuthenticator(
    os.Getenv("DATABRICKS_CLIENT_ID"),
    os.Getenv("DATABRICKS_CLIENT_SECRET"),
    os.Getenv("DATABRICKS_SERVER_HOSTNAME"),
)

connector, err := dbsql.NewConnector(
    dbsql.WithServerHostname(os.Getenv("DATABRICKS_SERVER_HOSTNAME")),
    dbsql.WithHTTPPath(os.Getenv("DATABRICKS_HTTP_PATH")),
    dbsql.WithPort(443),
    dbsql.WithAuthenticator(authenticator),
)
```

The required environment variables are:

- `DATABRICKS_SERVER_HOSTNAME`: The Server Hostname value for your cluster or SQL warehouse.
- `DATABRICKS_HTTP_PATH`: The HTTP Path value for your cluster or SQL warehouse.
- `DATABRICKS_CLIENT_ID`: The service principal’s UUID or Application ID value.
- `DATABRICKS_CLIENT_SECRET`: The Secret value for the service principal’s OAuth secret.

Set these environment variables according to your operating system's documentation.