Commit message specification

[dengn]

MatrixOne commit message is still not standardized. We need a commit specification to standardize our commit message format and limit the commit number in a pull request. Thanks to @noneback for bringing this out with issue #2126.

This discussion is started for determining about this specification. All proposals and comments are welcome.

[noneback]

• commit message : conventional commits
• commits number limitation: A PR should be implemented in one commit. If not, the original PR should be divided into several PRs