Update CONTRIBUTING.md

[RohitSgh]

Fixed Markdown

[RohitSgh]

Please check

Tagging
@dsmilkov
@shancarter

[mihaimaruseac]

Please don't use "add file"/"update file"/"fix file"/etc. commit messages. These are hard to reason about when looking at the history of the file/repository. Instead, please write explanatory git commit messages.

The commit message is also the title of the PR if the PR has only one commit. It is thus twice important to have commit messages that are relevant, as PRs would be easier to understand and easier to analyze in search results.

For how to write good quality git commit messages, please consult https://cbea.ms/git-commit/