Error about Private Key Authentication in documentation

[JonathanStefanov]

Describe the bug
In the Private Key Authentication of the readme documentation, it is said that the users should write the private key path in "private-key".

This is in fact not the case as pointed by @sfc-gh-astus in this thread snowflakedb/snowflake-cli#1480. Indeed one is supposed to use private_key_file

I was not able to use my account's private key for auth private-key in connections.toml but was able to with private_key_file. Using private-key gave the error TypeError: Expected bytes or RSAPrivateKey, got <class 'NoneType'> schemachange

To Reproduce
Create a connections.toml file like so
[xxxxxxxx]
account = "xxxx-xxxx"
user = "xxxx"
warehouse = "xxxx"
authenticator = "snowflake_jwt"
private-key = "rsa_key.p8"

Observe that it does not work

[xxxxxxxx]
account = "xxxx-xxxx"
user = "xxxx"
warehouse = "xxxx"
authenticator = "snowflake_jwt"
private_key_file = "rsa_key.p8"

Observe it works

Schemachange (please complete the following information):

• Version: 4.0.0