Update rustc-hash requirement from 1.1.0 to 2.1.0 (#2551)

---
updated-dependencies:
- dependency-name: rustc-hash
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

stacker/Cargo.toml

@@ -26,7 +26,7 @@ path = "example/hashmap.rs"
 [dev-dependencies]
 rand = "0.8.5"
 zipf = "7.0.0"
-rustc-hash = "1.1.0"
+rustc-hash = "2.1.0"
 proptest = "1.2.0"
 binggan = { version = "0.14.0" }