footer changed in README.md#155

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

JoseManuelAlvarezAlvarez:bug-fix-typoJoseManuelAlvarezAlvarez/mcino-Introduction-to-Git-and-GitHub:bug-fix-typoCopy head branch name to clipboard