python: Demonstrate pool use for psycopg3 #122
Description
The sample for psycopg 3 generates a token on every connection attempt. It should also show how to create a ConnectionPool that works with token refresh.
A caveat: psycopg/psycopg#851 indicates the entire connection pool must be recreated to update the connection string. There's agreement that credentials should be refreshed without recreating the pool work hasn't been started.