Support Google Cloud Run/SQL

[dakom]

Picking up from #144 (comment)

I am using Cloud Run + Cloud SQL (postgres) and the connection string which worked with diesel does not work out of the box with sqlx. I format it like this:

//note: things in all caps, that aren't env vars, are configurable / global constants

let socket_path = std::env::var("DB_SOCKET_PATH").unwrap_or("/cloudsql".to_string());
let instance_connection = std::env::var("INSTANCE_CONNECTION_NAME").unwrap_or(MY_INSTANCE_NAME.to_string());
let full_socket_path = utf8_percent_encode(&format!("{}/{}", socket_path, instance_connection), NON_ALPHANUMERIC).to_string();

format!("postgres://{}:{}@{}/{}", DB_USER, DB_PASS, full_socket_path, DB_NAME);

Any tips appreciated! I haven't tried the PgConnectOptions approach yet

[dakom]

Closing this since PgConnectOptions (on master) works, so whatever bug there is would be in the parsing, not specific to google cloud sql