Upgrade Billingo SDK

Upgrade billingo sdk sto 3.0.14

Update Guzzle version

v0.2.6

Fix: guzzle build_query

v0.2.5

Bugfix: guzzle http version support

v0.2.4

Update readme to v 3.0.13 SDK

v0.2.3

Update SDK and remove not used dev dependencies

• Update Billingo PHP SDK to 3.0.13
• Remove PHP Unit 4.8 from dev dependencies, because it's outdated and the SDK does not contains tests

v0.2.1

update readme file installation guide

v0.2.0

Update fork to Billingo API v3.0.11

v0.1.0

Update readme, add version tag