Update nitrokey crate to 0.2.3

This change updates the nitrokey crate to version 0.2.3. This version
bumps the rand crate used to 0.6.1, which in turn requires an additional
set of dependencies.

Import subrepo nitrokey/:nitrokey at b3e2adc5bb1300441ca74cc7672617c042f3ea31
Import subrepo rand/:rand at 73613ff903512e9503e41cc8ba9eae76269dc598
Import subrepo rustc_version/:rustc_version at 0294f2ba2018bf7be672abd53db351ce5055fa02
Import subrepo semver-parser/:semver-parser at 750da9b11a04125231b1fb293866ca036845acee
Import subrepo semver/:semver at 5eb6db94fa03f4d5c64a625a56188f496be47598

1 files changed, 65 insertions, 0 deletions

diff --git a/rand/rand_core/README.md b/rand/rand_core/README.md
new file mode 100644
index 0000000..dee6504
--- /dev/null
+++ b/rand/rand_core/README.md
@@ -0,0 +1,65 @@
+# rand_core
+
+[![Build Status](https://travis-ci.org/rust-random/rand.svg)](https://travis-ci.org/rust-random/rand)
+[![Build Status](https://ci.appveyor.com/api/projects/status/github/rust-random/rand?svg=true)](https://ci.appveyor.com/project/rust-random/rand)
+[![Latest version](https://img.shields.io/crates/v/rand_core.svg)](https://crates.io/crates/rand_core)
+[![Book](https://img.shields.io/badge/book-master-yellow.svg)](https://rust-random.github.io/book/)
+[![API](https://img.shields.io/badge/api-master-yellow.svg)](https://rust-random.github.io/rand/rand_core)
+[![API](https://docs.rs/rand_core/badge.svg)](https://docs.rs/rand_core)
+[![Minimum rustc version](https://img.shields.io/badge/rustc-1.22+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
+
+Core traits and error types of the [rand] library, plus tools for implementing
+RNGs.
+
+This crate is intended for use when implementing the core trait, `RngCore`; it
+defines the core traits to be implemented as well as several small functions to
+aid in their implementation and types required for error handling.
+
+The main [rand] crate re-exports most items defined in this crate, along with
+tools to convert the integer samples generated by `RngCore` to many different
+applications (including sampling from restricted ranges, conversion to floating
+point, list permutations and secure initialisation of RNGs). Most users should
+prefer to use the main [rand] crate.
+
+Links:
+
+-   [API documentation (master)](https://rust-random.github.io/rand/rand_core)
+-   [API documentation (docs.rs)](https://docs.rs/rand_core)
+-   [Changelog](CHANGELOG.md)
+
+[rand]: https://crates.io/crates/rand
+
+
+## Functionality
+
+The `rand_core` crate provides:
+
+-   base random number generator traits
+-   error-reporting types
+-   functionality to aid implementation of RNGs
+
+The traits and error types are also available via `rand`.
+
+## Crate Features
+
+`rand_core` supports `no_std` and `alloc`-only configurations, as well as full
+`std` functionality. The differences between `no_std` and full `std` are small,
+comprising `RngCore` support for `Box<R>` types where `R: RngCore`, as well as
+extensions to the `Error` type's functionality.
+
+Due to [rust-lang/cargo#1596](https://github.com/rust-lang/cargo/issues/1596),
+`rand_core` is built without `std` support by default. Since features are
+unioned across the whole dependency tree, any crate using `rand` with its
+default features will also enable `std` support in `rand_core`.
+
+The `serde1` feature can be used to derive `Serialize` and `Deserialize` for RNG
+implementations that use the `BlockRng` or `BlockRng64` wrappers.
+
+
+# License
+
+`rand_core` is distributed under the terms of both the MIT license and the
+Apache License (Version 2.0).
+
+See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT), and
+[COPYRIGHT](COPYRIGHT) for details.