说明：例如将代码提交到git仓库，将一些敏感信息提交，所以需要删除提交记录以彻底清除提交信息，以得到一个干净的仓库且代码不变
1.Checkout
git checkout --orphan latest_branch
2. Add all the files
git add -A
3. Commit the changes
git commit -am "commit message"
4. Delete the branch
git branch -D master
5.Rename the current branch to master
git branch -m master
6.Finally, force update your repository
git push -f origin master