Bump nix from 0.13.0 to 0.14.0 (#4382)

Bumps [nix](https://github.com/nix-rust/nix) from 0.13.0 to 0.14.0.
- [Release notes](https://github.com/nix-rust/nix/releases)
- [Changelog](https://github.com/nix-rust/nix/blob/master/CHANGELOG.md)
- [Commits](https://github.com/nix-rust/nix/compare/v0.13.0...v0.14.0)

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

core/Cargo.toml

@@ -36,7 +36,7 @@ jsonrpc-ws-server = "11.0.0"
 libc = "0.2.55"
 log = "0.4.2"
 memmap = { version = "0.7.0", optional = true }
-nix = "0.13.0"
+nix = "0.14.0"
 rand = "0.6.5"
 rand_chacha = "0.1.1"
 rayon = "1.0.0"