Final (?) 1.2.6 changelog tweaks

This file describes changes in Arti through the current release.  Once Arti

is more mature, we may switch to using a separate changelog for each crate.

# Arti 1.2.6 — ?? ???? ????

# Arti 1.2.6 — 1 August 2024

Arti 1.2.6 continues development on onion service client authorization,

the RPC subsystem, and relay infrastructure.

(Changelog Up-to-date as of 5eb74737a54041a39293344a5e0193465f4eb52d)

### Security fixes

- Update `openssl` to avoid undefined behavior in `MemBio::get_buf`.

  to onion services. ([#1281], [#1291], [!2212], [!2257])

- Support parsing client restricted discovery (a.k.a. "client authorization") keys

  from C Tor's `descriptor:x25519:<base32-encoded-x25519-public-key>` key format.

  ([#1292], [!2246])

  ([!2246])

- Ensure that `hsc` subcommand can build correctly with unusual combinations

  of features. ([!2254])

- Remove some unused code for publishing and authentication support.

  ([#1485], [!2255])

- Script to make sure that every crate has a valid set of crates.io

  categories. ([#1481], [!2256])

- Move our commonly used rust maintenance scripts to a seperate repository,

  imported with git-subtree. ([#1300], [!2267])

- Move our commonly used rust maintenance scripts to a separate repository,

  imported with `git-subtree`. ([#1300], [!2267])

- In gitlab CI, pin the compiler version we use to build cargo-audit

  and some other tools. ([!2289], [!2290])

### Cleanups, minor features, and bugfixes

- Remove an unused constant from `hashx`. ([!2243])

- Remove an unused constant from `equix`. ([!2243])

- Suppress and resolve a few warnings about documentation and dead code.

  ([!2244])

- Fix parsing time-periods from "key slug" identifiers. ([!2248])

Thanks to everybody who's contributed to this release, including

Alexander Færøy, Clara Engler, Jim Newsome, and trinity-1686a!

Also, our deep thanks to

[Zcash Community Grants],

the [Bureau of Democracy, Human Rights and Labor],