Upgrade rake to use version 13. Solves #7900 (#7910)
Upgrade rake to use version 13. Solves #7900 (#7910)

Merge pull request 7910
tillgrallert/jekyll,tillgrallert/jekyll,tillgrallert/jekyll,x-way/jekyll,fulldecent/jekyll,chrisfinazzo/jekyll,yhironaka/yhironaka.github.io,jaybe-jekyll/jekyll,jaybe-jekyll/jekyll,fulldecent/jekyll,x-way/jekyll,jekyll/jekyll,ryanshaw/jekyll,ryanshaw/jekyll,chrisfinazzo/jekyll,x-way/jekyll,ryanshaw/jekyll,jekyll/jekyll,chrisfinazzo/jekyll,jekyll/jekyll,tillgrallert/jekyll,chrisfinazzo/jekyll,tillgrallert/jekyll,x-way/jekyll,jekyll/jekyll,jaybe-jekyll/jekyll,fulldecent/jekyll,jaybe-jekyll/jekyll,fulldecent/jekyll,ryanshaw/jekyll