Bump rand from 0.8.5 to 0.8.6 in /library/stdarch

Bumps [rand](https://github.com/rust-random/rand) from 0.8.5 to 0.8.6.
- [Release notes](https://github.com/rust-random/rand/releases)
- [Changelog](https://github.com/rust-random/rand/blob/0.8.6/CHANGELOG.md)
- [Commits](rust-random/rand@0.8.5...0.8.6)

---
updated-dependencies:
- dependency-name: rand
  dependency-version: 0.8.6
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

library/stdarch/Cargo.lock

@@ -7,4 +7,4 @@ edition = "2024"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-rand = "0.8.5"
+rand = "0.8.6"