Update semver-compatible dependencies, apply nightly clippy suggestions

[djc]

No description provided.

[cpu]

Looks like there's one last clippy format string finding:

error: variables can be used directly in the `format!` string
  --> librustls/tests/client_server.rs:11:23
   |
11 |     let server_addr = format!("{}:{}", HOST, PORT);
   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^