Define workflow with git

[GimmyHchs]

Resolve a github issue

• Always checkout from origin/main
• You must create an issue before creating a pull request
• The branch name should be ISSUE-XX eg. ISSUE-2
• The PR title should be [ISSUE-XX] your-pull-request-title
• Squash merge the PR
  • Why-1: We can make sure that every commits are significant in master branch
  • Why-2: We don't need to care about your commit message when review PR
• Merge message follow the commit convention
  • ex: docs: add pull request template