Increase recommended Rust toolchain to 1.77.2

[mulkieran]

• [x] Give karma for f39 Rust release: https://bodhi.fedoraproject.org/updates/FEDORA-2024-6bc17db348

• [x] Bump current development toolchain in GitHub workflows

  • [x] devicemapper-rs
  • [x] libblkid-rs
  • [x] libcryptsetup-rs
  • [x] loopdev-3
  • [x] stratisd
  • [x] stratis-cli