Update Ruby version used in Travis-CI example (#7783)
Update Ruby version used in Travis-CI example (#7783)

Merge pull request 7783
fulldecent/jekyll,jaybe-jekyll/jekyll,x-way/jekyll,ryanshaw/jekyll,jaybe-jekyll/jekyll,tillgrallert/jekyll,chrisfinazzo/jekyll,x-way/jekyll,tillgrallert/jekyll,chrisfinazzo/jekyll,yhironaka/yhironaka.github.io,jekyll/jekyll,tillgrallert/jekyll,chrisfinazzo/jekyll,fulldecent/jekyll,ryanshaw/jekyll,jekyll/jekyll,jekyll/jekyll,ryanshaw/jekyll,ryanshaw/jekyll,x-way/jekyll,fulldecent/jekyll,chrisfinazzo/jekyll,tillgrallert/jekyll,jaybe-jekyll/jekyll,jaybe-jekyll/jekyll,jekyll/jekyll,x-way/jekyll,fulldecent/jekyll,tillgrallert/jekyll