This pulls in versions of previously nightly-only crates that can be
built on 1.65 beta.
The Cargo overrides that direct the resolver to the git repositories are
disabled while the version used in tree also happens to be a released
version of the crates, as it should be the case as per [251].
[251]: https://github.com/RIOT-OS/Release-Specs/issues/251
This makes it easier for all maintainers to adjust to C-nonbreaking but
Rust-breaking API changes, as regular `cargo update` steps don't require
a crates.io release any more.
