Update openssh-sftp-client requirement from 0.11.0 to 0.12.0

Updates the requirements on [openssh-sftp-client](https://github.com/openssh-rust/openssh-sftp-client) to permit the latest version.
- [Release notes](https://github.com/openssh-rust/openssh-sftp-client/releases)
- [Commits](https://github.com/openssh-rust/openssh-sftp-client/commits)

---
updated-dependencies:
- dependency-name: openssh-sftp-client
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Cargo.toml

@@ -52,7 +52,7 @@ openssh-mux-client = { version = "0.15.1", optional = true }
 [dev-dependencies]
 regex = "1"
 tokio = { version = "1", features = [ "full" ] }
-openssh-sftp-client = "0.11.0"
+openssh-sftp-client = "0.12.0"
 
 [[example]]
 name = "native-mux_tsp"