Can't meet PHP ^7.1 dep requirements

[ghost]

Description

Given our hosting solution, we are unable to upgrade beyond PHP 7.0, making the PHP ^7.1 requirement for installing dependencies impossible for us.

Expected behaviour

composer install should install all of the dependencies

Actual behaviour

We get an error in the console as follows:

Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Installation request for doctrine/instantiator 1.1.0 -> satisfiable by doctrine/instantiator[1.1.0].
    - doctrine/instantiator 1.1.0 requires php ^7.1 -> your PHP version (7.0.19) does not satisfy that requirement.
  Problem 2
    - Installation request for symfony/yaml v4.0.1 -> satisfiable by symfony/yaml[v4.0.1].
    - symfony/yaml v4.0.1 requires php ^7.1.3 -> your PHP version (7.0.19) does not satisfy that requirement.
  Problem 3
    - doctrine/instantiator 1.1.0 requires php ^7.1 -> your PHP version (7.0.19) does not satisfy that requirement.
    - phpunit/phpunit-mock-objects 3.4.4 requires doctrine/instantiator ^1.0.2 -> satisfiable by doctrine/instantiator[1.1.0].
    - Installation request for phpunit/phpunit-mock-objects 3.4.4 -> satisfiable by phpunit/phpunit-mock-objects[3.4.4].

Steps to reproduce the problem

Install PHP version 7.0.x and attempt to install dependencies for the plugin via composer install

System Information

• Pressbooks mPDF: 3.0.0
• Pressbooks: 4.5.0
• WordPress: 4.9.1

[greatislander]

composer install --no-dev should work as those dependencies are only for unit testing.

[ghost]

Ah yes, thank you @greatislander. Oversight on my part. :)