Increase recommended Rust toolchain to 1.73.0

[mulkieran]

• [x] Fix any newly introduced compiler or clippy errors:

  • [x] devicemapper-rs
  • [x] libblkid-rs
  • [x] libcryptsetup-rs
  • [x] stratisd

• [x] Give karma for f38 Rust release: https://bodhi.fedoraproject.org/updates/FEDORA-2023-c1d2c8e17c

• [x] Bump current development toolchain in GitHub workflows

  • [x] devicemapper-rs
  • [x] libblkid-rs
  • [x] libcryptsetup-rs
  • [x] stratisd
  • [x] stratis-cli

[bgurney-rh]

There were no compiler or clippy errors in libblkid-rs or libcryptsetup-rs.