build(deps): update futures-timer requirement from ^2.0 to ^3.0

Updates the requirements on [futures-timer](https://github.com/async-rs/futures-timer) to permit the latest version.
- [Release notes](https://github.com/async-rs/futures-timer/releases)
- [Commits](async-rs/futures-timer@2.0.1...v3.0.0)

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

heim-process/Cargo.toml

@@ -56,7 +56,7 @@ darwin-libproc = "0.1.1"
 futures-executor = "^0.3"
 version-sync = "0.8"
 pin-utils = "0.1.0-alpha.4"
-futures-timer = "^2.0"
+futures-timer = "^3.0"
 which = "~3.1"
 
 [features]