build: bump libc from 0.2.119 to 0.2.120

Bumps [libc](https://github.com/rust-lang/libc) from 0.2.119 to 0.2.120.
- [Release notes](https://github.com/rust-lang/libc/releases)
- [Commits](https://github.com/rust-lang/libc/compare/0.2.119...0.2.120)

---
updated-dependencies:
- dependency-name: libc
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

vm-allocator/Cargo.toml

@@ -5,6 +5,6 @@ authors = ["The Chromium OS Authors"]
 edition = "2018"
 
 [dependencies]
-libc = "0.2.119"
+libc = "0.2.120"
 vm-memory = "0.7.0"
 arch = { path = "../arch" }