Migrate to new php

[tarampampam]

Q	A
Bug fix?	Yes or No
New feature?	Yes or No

Description

Added

• Docker-based environment for development
• Project Makefile

Changed

• Minimal PHP version now is ^7.1.3
• Maximal Laravel version now is 5.8.x
• Dependency laravel/framework changed to illuminate/*
• Composer scripts
• Argument and return types
• Class \AvtoDev\StaticReferences\StaticReferencesServiceProvider renamed to \AvtoDev\StaticReferences\ServiceProvider
• Service provider dependency \Illuminate\Contracts\Foundation\Application changed to \Illuminate\Contracts\Container\Container

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I wrote unit tests for my code
• I have made changes in CHANGELOG.md file