Issue #26 let's use py38

tox.ini

@@ -1,12 +1,12 @@
 # content of: tox.ini , put in same dir as setup.py
 [tox]
-envlist = py37,lint
+envlist = py38,lint
 skipsdist = True
 requires = setuptools >= 47.1
 
 [travis]
 python =
-  3.7: py37, docs, lint
+  3.8: py38, docs, lint
 
 [testenv]
 passenv = *
@@ -18,22 +18,22 @@ commands = coverage erase
            coverage report -m
 
 [testenv:lint]
-basepython=python3.7
+basepython=python3.8
 deps=pylint
      {[testenv]deps}
 commands=pylint --rcfile=tests/pylintrc snappysonic tests
 
 [testenv:docs]
-basepython=python3.7
+basepython=python3.8
 changedir = doc
 commands = sphinx-build -M html . build
 
 [testenv:installer]
-basepython=python3.7
+basepython=python3.8
 commands=pyinstaller --onefile snappysonic.py --noconfirm --windowed
 
 [testenv:pip3]
-basepython=python3.7
+basepython=python3.8
 changedir=pip_test
 skip_install=True
 commands = pip install {posargs}