Fixes #1888: Default to PHP 7.1.

[grasmash]

No description provided.

[grasmash]

@danepowell @geerlingguy @mikemadison13 Will this have any notable consequences that I should be aware of?

[geerlingguy]

@grasmash - You mean, besides everything being like 50% faster? Nope.

[danepowell]

Won't this prevent BLT from being installed or run on host machines using PHP <7?

[dpagini]

Curious about this answer...? Also, if this is the general approach of BLT, can't we undo #1829 as well?

[danepowell]

We should also set up Pipelines to use PHP7:

version: 1.1.0
services:
  - mysql
  - php:
      version: 7.1

We should also make sure to include release notes indicating that the default versions have changed, and folks should re-initialize DrupalVM, Travis, and Pipelines to get the change locally.

[mikemadison13]

People will def. need to change back to 5.6 if not running 7. That will cause problems for sure.