Update pg-connection-string url in connecting.mdx (brianc#3005)

Author: rikurauhala

docs/pages/features/connecting.mdx

@@ -127,7 +127,7 @@ client = new Client({
 
 ## Connection URI
 
-You can initialize both a pool and a client with a connection string URI as well. This is common in environments like Heroku where the database connection string is supplied to your application dyno through an environment variable. Connection string parsing brought to you by [pg-connection-string](https://github.com/iceddev/pg-connection-string).
+You can initialize both a pool and a client with a connection string URI as well. This is common in environments like Heroku where the database connection string is supplied to your application dyno through an environment variable. Connection string parsing brought to you by [pg-connection-string](https://github.com/brianc/node-postgres/tree/master/packages/pg-connection-string).
 
 ```js
 import { Pool, Client } from 'pg'