chore: remove python35 and 34 and add 39

Author: elliottmurray

.github/workflows/build_and_test.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.4, 3.5, 3.6, 3.7, 3.8]
+        python-version: [3.6, 3.7, 3.8, 3.9]
 
     steps:
     - uses: actions/checkout@v2

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist=py{34,35,36,37,38}-{test,install}
+envlist=py{36,37,38,39}-{test,install}
 [testenv]
 deps=
     test: -rrequirements_dev.txt