Update CODE_OF_CONDUCT.md (#4468)

* Update CODE_OF_CONDUCT.md

Code of Conduct typically means how contributor should behave in this community. The current contents here are helpful coding syle guide.
It is also best to rename the filename to "CODE_STYLE_GUIDE.md"

* Rename CODE_OF_CONDUCT.md to Coding_Style_Guide.md

as suggested

CODE_OF_CONDUCT.md → Coding_Style_Guide.md

@@ -1,4 +1,4 @@
-# Contributor Covenant Code of Conduct
+# Contributor Covenant Coding Style Guide
 
 Currently we use clang-format to format the code. We recommend you to configure the clang-format according to the IDE / editor you use. The following link is how to configure vim / emacs / vscode to use clang-format.