[cli.alias] green = "fmt lint check" --all-changed = "--changed-since=HEAD --changed-dependents=transitive"
This would allow you to run pants green --all-changed, which is shorthand for pants fmt lint check --changed-since=HEAD --changed-dependents=transitive.
Notice: this option must be placed in a config file (e.g. pants.toml or pantsrc) to have any effect.