updated CONTRIBUTING.md regarding clang-format tool version

CONTRIBUTING.md

@@ -105,10 +105,10 @@ The commands above will automatically install all the dependencies using [Python
 
 ### 4. Format source files
 
-[GitHub Actions](https://github.com/fktn-k/fkYAML/actions) will test the updated project with the [Clang-Format](https://releases.llvm.org/14.0.0/tools/clang/docs/ClangFormat.html) tool (14.0.0) once you open a PR or push commits afterwards which include changes in the source files under either [`include`](https://github.com/fktn-k/fkYAML/tree/develop/include) or [`test`](https://github.com/fktn-k/fkYAML/tree/develop/test) directories.  
+[GitHub Actions](https://github.com/fktn-k/fkYAML/actions) will test the updated project with the [Clang-Format](https://github.com/llvm/llvm-project/releases/tag/llvmorg-18.1.3) tool (18.1.3) once you open a PR or push commits afterwards which include changes in the source files under either [`include`](https://github.com/fktn-k/fkYAML/tree/develop/include) or [`test`](https://github.com/fktn-k/fkYAML/tree/develop/test) directories.  
 Although code formatting is automatically executed in the GitHub Actions workflows, you can run the script files ([`run_clang_format.bat`](https://github.com/fktn-k/fkYAML/scripts/run_clang_format.bat) for Windows, [`run_clang_format.sh`](https://github.com/fktn-k/fkYAML/scripts/run_clang_format.sh) otherwise) to check if your changes follow the rules defined in the [`.clang-format`](https://github.com/fktn-k/fkYAML/tree/develop/.clang-format) file on your local environment in advance.  
 Note that, since the Clang-Format tool does not gurantee backward compatibility especially in its edge cases and its behaviors might therefore vary from version to version, it's highly recommended that you use the above script files to avoid unnecessary confusion for that kind of reason.  
-The scripts uses [the Clang-Format Python distribution](https://pypi.org/project/clang-format/14.0.0/) and installs it using [the Python venv module](https://docs.python.org/3/library/venv.html) if it's not been installed yet.  
+The scripts uses [the Clang-Format Python distribution](https://pypi.org/project/clang-format/18.1.3/) and installs it using [the Python venv module](https://docs.python.org/3/library/venv.html) if it's not been installed yet.  
 You can run the scripts with the following commands:  
 
 **Windows (Command Prompt)**