more detailed error message when SSH_AUTH_SOCK points to a bad location

Dependencies

• [2] 2WEO7OZL Version updates: getting rid of anyhow + moving to Tokio 1.0
• [3] 7FRJYUI6 Reboot because of a bad change
• [4] 55M4M5YU Fake agent client on Windows

Change contents

• edit in thrussh-keys/src/lib.rs at line 127
  [2.433]

  [3.27374]
  + #[error("Unable to connect to ssh-agent. The environment variable `SSH_AUTH_SOCK` \

  + was set, but it points to a nonexistent file or directory.")]

  + BadAuthSock,
• replacement in thrussh-keys/src/agent/client.rs at line 50
  [2.3141]→[3.140571:140608](∅→∅),[3.140571]→[3.140571:140608](∅→∅)
  − Self::connect_uds(var).await
  [2.3141]

  [3.140608]
  + match Self::connect_uds(var).await {

  + Err(Error::IO(io_err)) if io_err.kind() == std::io::ErrorKind::NotFound => Err(Error::BadAuthSock),

  + owise => owise

  + }