Use ^1.4 for composer/composer

[sandermangel]

Some modules require a more recent version of composer. To allow for this we use "^1.4" for the composer version

Description

Using the "1.4 and above" will mean it's backwards compatible for current use of 1.4 and uses newer versions in installations where possible.
This will allow for installing modules that use newer versions

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-cicd2]

All committers have signed the CLA.

[miguelbalparda]

Thanks for your contribution Sander! This is going to be reviewed soon, I'll let you know if we have questions!

[magento-engcom-team]

Hi @miguelbalparda, thank you for the review.
ENGCOM-809 has been created to process this Pull Request

[magento-engcom-team]

@sandermangel thank you for contributing. Please accept Community Contributors team invitation here to gain extended permissions for this repository.

[sandermangel]

@magento-engcom-team thanks guys, happy to see this going through!