drop python 3.5, 3.6 .. add pythons up to 3.10

.github/workflows/test.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.5, 3.6, 3.7, 3.8, 3.9]
+        python-version: [3.7, 3.8, 3.9, 3.10]
 
     steps:
     - uses: actions/checkout@v2

tox.ini

@@ -4,7 +4,7 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = {py35,py36,py37,pypy}
+envlist = {py37,py38,py39,py310,pypy}
 skip_missing_interpreters = True
 minversion = 2.4.0