[DO NOT MERGE] Allow git deps for rustc-stable-hash

Author: Urgau

src/tools/tidy/src/extdeps.rs

@@ -9,6 +9,7 @@ const ALLOWED_SOURCES: &[&str] = &[
     r#""registry+https://github.com/rust-lang/crates.io-index""#,
     // This is `rust_team_data` used by `site` in src/tools/rustc-perf,
     r#""git+https://github.com/rust-lang/team#a5260e76d3aa894c64c56e6ddc8545b9a98043ec""#,
+    r#""git+https://github.com/rust-lang/rustc-stable-hash?rev=3805516#3805516b78c7b2946ae2071d71ffc8235399652d""#,
 ];
 
 /// Checks for external package sources. `root` is the path to the directory that contains the