Support more environment variables in PostgreSQL container

[ksquaredkey]

With the move from md5 to scram-sha-256 in the PostgreSQL 14.x containers, I find myself needing to set the POSTGRES_HOST_AUTH_METHOD and potentially POSTGRES_INITDB_ARGS. Seems like it would be good to flesh out the rest of the currently supported environment variables of the official PostgreSQL container. The ones not yet supported are:

• POSTGRES_INITDB_ARGS
• POSTGRES_INITDB_WALDIR
• POSTGRES_HOST_AUTH_METHOD
• PGDATA

[santi]

These environment variables can be set through the .with_env(<env_var>, <value>) API on the container itself. Like this:

container = (
    PostgresContainer("postgres:16", driver="pg8000")
    .with_env("POSTGRES_INITDB_ARGS", "args here")
    .with_env("POSTGRES_INITDB_WALDIR", "args here")
)
with container as postgres:
    ...

[ksquaredkey]

Nice - thanks @santi ! I haven't had the cycles to come back and refactor my original PR but this is a much cleaner, flexible method, so no need.