Cleanup tox.ini

Remove 'linting' environment because we now rely directly on pre-commit.ci for this validation.

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 isolated_build = True
-envlist = py36, py37, py38, py39, linting
+envlist = py{38,39,310}
 
 [testenv]
 download=true
@@ -14,10 +14,3 @@ deps=
 commands =
     inv cog --check
     pytest --basetemp={envtmpdir} --cov={envsitepackagesdir}/alfasim_sdk --cov=tests --cov-report=xml --color=yes {posargs}
-
-
-[testenv:linting]
-skip_install = True
-basepython = python3.6
-deps = pre-commit>=1.11.0
-commands = pre-commit run --all-files --show-diff-on-failure