Update MajorVer for PHP7

[charsme]

Need This feature for publishing platform Publishing use php version 7 min, preferably php ^7.1, so guzzle 6.x used. Need to update dependencies and refactor to complement this

Solution Update guzzle version and php min version.

Alternative Polyfill but not recommended as it is heavy

To DO:

• [x] Migrate current branch to another branch for php 5.x neccesities
• [x] Composer update require Version for php and guzzle
• [x] phpunit to dev, remove binary, php-cs-fixer to ecs remove binary
• [x] Unit testing based on latest phpunit version
• [x] Refactor Publisher.php Script as needed
• [x] Do the same to klygarage/laravel-onesdk
• [ ] Update gh-pages
• [x] Refactor all neccesary script to comply guzzle 6
• [x] Refactor all neccesary script to comply ecs check

[charsme]

@kennykarnama @yasinmuhajir @martinocatur Tolong dahulukan issue ini dong. Biar publishing segera update ke versi guzzle baru, di commit message sementara selalu sertakan [skip ci] agar tidak keproses ci dulu. Bisa tolong handle berdasar error di composer run test

@martinocatur, @yasinmuhajir Tolong sesuaikan Publisher.php nya dahulu. Untuk pake client dari guzzle baru. Seingetku ganti namespace dan lokasi client.