bash-prg-hash: fix entry in CHANGELOG.md

Author: makavity

bash-prg-hash/CHANGELOG.md

@@ -7,6 +7,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 
 ## 0.1.0 (UNRELEASED)
-- Initial release ([#745])
+- Initial release ([#751])
 
-[#745]: https://github.com/RustCrypto/hashes/pull/745
+[#745]: https://github.com/RustCrypto/hashes/pull/751