docs: client_protocol_version missing from Connection Parameters table

The README references client_protocol_version under "Client Transfer Protocol," stating it can modify the protocol version. However, this parameter is:

1. Absent from the Connection Parameters table


2. Has no usage example or valid values documented

Suggested addition to the parameters table:

Parameter | Type | Default | Description
-- | -- | -- | --
client_protocol_version | int | 2 | Controls the wire protocol version for data transfer

Example:

conn = redshift_connector.connect(

    host='cluster.abc123.us-east-1.redshift.amazonaws.com',

    database='dev',

    user='admin',

    password='***',

    client_protocol_version=2

)

Happy to open a PR if maintainers can confirm the valid values.