Use rustls 0.21.9, revert nightly pin, update version to 0.11.1

[cpu]

• Updates to Rustls 0.21.9
• Opts in to core_io_borrowed_buf when using read_buf feature
• Reverts fix build: pin a specific nightly #361
• Updates crate version from 0.11.0 to 0.11.1
• Bumps semver compatible dependencies:
  • sct v0.7.0 -> v0.7.1 (Notably this prevents having two ring versions in the dep tree)
  • base64 v0.21.4 -> v0.21.5
  • libc v0.2.149 -> v0.2.150
  • rustls-pemfile v1.0.3 -> v1.0.4

I left out a dev-dependency update for the regex crate (v1.9.6 -> v1.10.2) since it bumps the MSRV to 1.65.

[jsha]

Thanks!