docs: Fix installation command on macOS for stackablectl #48

Job	Run time
General Pull Request Checks / Run Cargo Deny (advisories)	44s
General Pull Request Checks / Run Clippy	1m 18s
General Pull Request Checks / Run Cargo Deny (bans licenses sources)	48s
General Pull Request Checks / Run RustDoc	1m 48s
General Pull Request Checks / Run Rustfmt	13s
General Pull Request Checks / Run Cargo Tests	1m 11s
General Pull Request Checks / Run Cargo Udeps	1m 49s
General Pull Request Checks / All tests passed	1s
	7m 52s

Provide feedback