Update README and CHANGELOG

Author: flip1995

rustc_tools_util/CHANGELOG.md

@@ -1,5 +1,14 @@
 # Changelog
 
+## Version 0.4.0
+
+* The commit hashes are now always 10 characters long [#13222](https://github.com/rust-lang/rust-clippy/pull/13222)
+* `get_commit_date` and `get_commit_hash` now return `None` if the `git` command fails instead of `Some("")`
+  [#13217](https://github.com/rust-lang/rust-clippy/pull/13217)
+* `setup_version_info` will now re-run when the git commit changes
+  [#13329](https://github.com/rust-lang/rust-clippy/pull/13329)
+* New `rerun_if_git_changes` function was added [#13329](https://github.com/rust-lang/rust-clippy/pull/13329)
+
 ## Version 0.3.0
 
 * Added `setup_version_info!();` macro for automated scripts.

rustc_tools_util/README.md

@@ -13,10 +13,10 @@ build = "build.rs"
 List rustc_tools_util as regular AND build dependency.
 ````toml
 [dependencies]
-rustc_tools_util = "0.3.0"
+rustc_tools_util = "0.4.0"
 
 [build-dependencies]
-rustc_tools_util = "0.3.0"
+rustc_tools_util = "0.4.0"
 ````
 
 In `build.rs`, generate the data in your `main()`