refactor: remove tox py3X tests

tox.ini

@@ -1,41 +1,12 @@
 [tox]
-envlist = {py35, py36, py38, py310}-{test, flake8}, mypy, black, isort, shellcheck
-
-[testenv:py35-flake8]
-setuptools_version = 20.7.0
-
-[testenv:py35-test]
-setuptools_version = 20.7.0
-
-[testenv:py36-flake8]
-setuptools_version = 39.0.1
-
-[testenv:py36-test]
-setuptools_version = 39.0.1
-
-[testenv:py38-flake8]
-setuptools_version = 45.2.0
-
-[testenv:py38-test]
-setuptools_version = 45.2.0
-
-[testenv:py310-flake8]
-setuptools_version = 59.6.0
-
-[testenv:py310-test]
-setuptools_version = 59.6.0
+envlist = test, flake8, mypy, black, isort, shellcheck
 
 [testenv]
 allowlist_externals=/usr/bin/bash
 deps =
-    -rrequirements.txt
-    -rtest-requirements.txt
-    py35: -cuaclient/tests/constraints/constraints-xenial.txt
-    py36: -cuaclient/tests/constraints/constraints-bionic.txt
-    py38: -cuaclient/tests/constraints/constraints-focal.txt
-    py310: -cuaclient/tests/constraints/constraints-jammy.txt
+    test,mypy,flake8: -rrequirements.txt
+    test,mypy,flake8: -rtest-requirements.txt
     mypy: -rtypes-requirements.txt
-    mypy: -cuaclient/tests/constraints/constraints-mypy.txt
     black: -rdev-requirements.txt
     isort: -rdev-requirements.txt
     behave: -rintegration-requirements.txt
@@ -61,9 +32,7 @@ setenv =
 commands =
     test: py.test --junitxml=pytest_results.xml {posargs:--cov uaclient uaclient}
     flake8: flake8 uaclient lib setup.py features
-    mypy: mypy --python-version 3.6 uaclient/ features/ lib/
-    mypy: mypy --python-version 3.8 uaclient/ features/ lib/
-    mypy: mypy --python-version 3.10 uaclient/ features/ lib/
+    mypy: mypy uaclient/ features/ lib/
     black: black --check --diff uaclient/ features/ lib/ setup.py
     isort: isort --check --diff uaclient/ features/ lib/ setup.py
     shellcheck: bash -O extglob -O nullglob -c "shellcheck -S warning tools/*.sh debian/*.{config,postinst,postrm,prerm} lib/*.sh sru/*.sh update-motd.d/*"