Vendor dependencies

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vendor/rand_core/CHANGELOG.md

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+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [0.4.2] - 2019-08-01
+Back-port non-API changes from version 0.5.0:
+- Enable testing with Miri and fix incorrect pointer usages (#779, #780, #781, #783, #784)
+- Adjust usage of `#[inline]` for `BlockRng` and `BlockRng64`
+
+## [0.4.0] - 2019-01-24
+- Disable the `std` feature by default (#702)
+
+## [0.3.0] - 2018-09-24
+- Add `SeedableRng::seed_from_u64` for convenient seeding. (#537)
+
+## [0.2.1] - 2018-06-08
+- References to a `CryptoRng` now also implement `CryptoRng`. (#470)
+
+## [0.2.0] - 2018-05-21
+- Enable the `std` feature by default. (#409)
+- Remove `BlockRng{64}::inner` and `BlockRng::inner_mut`; instead making `core` public
+- Add `BlockRng{64}::index` and `BlockRng{64}::generate_and_set`. (#374, #419)
+- Change `BlockRngCore::Results` bound to also require `AsMut<[Self::Item]>`. (#419)
+- Implement `std::io::Read` for RngCore. (#434)
+
+## [0.1.0] - 2018-04-17
+(Split out of the Rand crate, changes here are relative to rand 0.4.2)
+- `RngCore` and `SeedableRng` are now part of `rand_core`. (#288)
+- Add modules to help implementing RNGs `impl` and `le`. (#209, #228)
+- Add `Error` and `ErrorKind`. (#225)
+- Add `CryptoRng` marker trait. (#273)
+- Add `BlockRngCore` trait. (#281)
+- Add `BlockRng` and `BlockRng64` wrappers to help implementations. (#281, #325)
+- Revise the `SeedableRng` trait. (#233)
+- Remove default implementations for `RngCore::next_u64` and `RngCore::fill_bytes`. (#288)
+- Add `RngCore::try_fill_bytes`. (#225)
+
+## [0.0.1] - 2017-09-14 (yanked)
+Experimental version as part of the rand crate refactor.