BrowserStack: add Firefox 60 and Chrome 60 (#34912)
BrowserStack: add Firefox 60 and Chrome 60 (#34912)

These are the minimum supported versions, so this patch makes sure everything works there too.
m5o/bootstrap,twbs/bootstrap,coliff/bootstrap,m5o/bootstrap,coliff/bootstrap,tjkohli/bootstrap,inway/bootstrap,twbs/bootstrap,tjkohli/bootstrap,inway/bootstrap,inway/bootstrap