bump version to 0.8.1

support anonymous mutations and subscriptions

use full query syntax in the readme example instead of shorthand

codestyle

bump version to 0.8.0

claim compatibility with Python 3.9

add Python 3.7 - 3.9 to the test matrix

fixing identation

adding subscription parsing & tests

bump version to 0.7.1

support anonymous queries

Parse true/false/null to python type True/False/None (Fixes #10)

fix classifiers in setup.py

readme: mention compatibility with Python 3.5 and 3.6

add Python 3.5 and 3.6 to tests matrix