Function cache_key 

pub fn cache_key(subject_type: &str, subject_id: &str, revision: &str) -> String

Build a deterministic cache key from a subject type and identifier.

Examples

use libverify_core::cache::cache_key;
assert_eq!(cache_key("pr", "owner/repo#42", "abc1234"), "pr:owner/repo#42:abc1234");