Update text and external link icon on Download page
Update text and external link icon on Download page

gocd/gocd.github.io,ketan/www.go.cd,gocd/www.go.cd,gocd/gocd.github.io,GaneshSPatil/www.go.cd,GaneshSPatil/www.go.cd,ketan/www.go.cd,GaneshSPatil/www.go.cd,gocd/gocd.github.io,ketan/gocd.github.io,GaneshSPatil/www.go.cd,gocd/www.go.cd,ketan/gocd.github.io,gocd/www.go.cd,ketan/gocd.github.io,ketan/www.go.cd,gocd/gocd.github.io,gocd/www.go.cd