dependabot update to symfony/process

Dependabot notified me that this needed updating, so I submitted a minor patch to cope with some infection dependency changes, and then re-checked the PR for symfony.

Please let me know if there is anything the test-suite, mutation testing (what infection is for) and static analysis did not catch.

Deprecation of PHP below 7.3

• Added GitHub CI
• Deprecated PHP 7.2, 7.1, 7.0 (they are all EOL for some time now)
• Restriction of PHP7.4 mentioned in README.md

This is a dead library 😄 Don't use it please 🙏

Separation of files

So when I made this I was a little lazy. @garak once again contributed fixes for my laziness and updated PHPUnit too. 🥇 👍

composer updates

#11 to fix my lax approach to "if it works it's fine" 👍 🥇 for sticking with me @garak

Injectable Time-Source

• Added Injectable Time-Source
• Interface TimeSourceInterface added
• Implementation of TimeSourceInterface from legacy PHP time() source added PHPTimeSource

CI & Testing Information Added

• Added unit-testing information
• Added code coverage information (with unit-testing info)
• Added Injectable Source of Randomness
• Interface RandomFloatInterface added
• Implementation of RandomFloatInterface from legacy PHP lcg_value() source of randomness added LcgRandomGenerator

Initial Stable Release

1.0

Update README.md