fix README.md footer date#1314

Daption-ciray wants to merge 1 commit intoibm-developer-skills-network:mainibm-developer-skills-network/mcino-Introduction-to-Git-and-GitHub:mainfrom

Daption-ciray:bug-fix-typoDaption-ciray/mcino-Introduction-to-Git-and-GitHub:bug-fix-typoCopy head branch name to clipboard