Add badges to README (#7)

Author: biozz

README.md

@@ -1,5 +1,11 @@
 # pAPI SDK
 
+![main workflow](https://github.com/ostrovok-team/papi-sdk-python/workflows/Main/badge.svg)
+![pypi version](https://img.shields.io/pypi/v/papi-sdk.svg)
+![pypi downloads](https://img.shields.io/pypi/dm/papi-sdk.svg)
+![python versions](https://img.shields.io/pypi/pyversions/papi-sdk.svg)
+![license](https://img.shields.io/github/license/ostrovok-team/papi-sdk-python.svg)
+
 pAPI SDK is a python SDK for [ETG APIv3](https://docs.emergingtravel.com/).
 The abbreviation "pAPI" stands for "Partner API".