snowflakeauth 0.2.1

• Misleading warnings about the config.toml and connections.toml files both
  existing have been removed (#25).
• Error messages when a named connection is requested but the connections.toml
  file does not exist are now clearer (#23).
• Error messages when connections.toml exists but lacks a needed connection are
  now more specific and helpful (#26).
• externalbrowser authentication is now supported.