Minimal update to tox.ini for tests to pass

- remove pip.sh
- unpin top level requirements
- update charm-tools version for pep8 test
- update osci.yaml tox_extra_args for compatibility

Signed-off-by: Rafael Lopez <rafael.lopez@canonical.com>
Change-Id: Iec9fbd296d6d5b5fa647739d5588218c28e0a773

osci.yaml

@@ -16,4 +16,4 @@
       - osci-lint
       - tox-py36
     vars:
-      tox_extra_args: bionic_model:bionic-ha
+      tox_extra_args: '-- bionic_model:bionic-ha'

pip.sh

@@ -1,18 +0,0 @@
-#!/usr/bin/env bash
-#
-# This file is managed centrally by release-tools and should not be modified
-# within individual charm repos.  See the 'global' dir contents for available
-# choices of tox.ini for OpenStack Charms:
-#     https://github.com/openstack-charmers/release-tools
-#
-# setuptools 58.0 dropped the support for use_2to3=true which is needed to
-# install blessings (an indirect dependency of charm-tools).
-#
-# More details on the beahvior of tox and virtualenv creation can be found at
-# https://github.com/tox-dev/tox/issues/448
-#
-# This script is wrapper to force the use of the pinned versions early in the
-# process when the virtualenv was created and upgraded before installing the
-# depedencies declared in the target.
-pip install 'pip<20.3' 'setuptools<50.0.0'
-pip "$@"

tox.ini

@@ -22,25 +22,21 @@ skip_missing_interpreters = False
 # * It is also necessary to pin virtualenv as a newer virtualenv would still
 #   lead to fetching the latest pip in the func* tox targets, see
 #   https://stackoverflow.com/a/38133283
-requires =
-  pip < 20.3
-  virtualenv < 20.0
-  setuptools < 50.0.0
-
-# NOTE: https://wiki.canonical.com/engineering/OpenStack/InstallLatestToxOnOsci
-minversion = 3.18.0
 
 [testenv]
 setenv = VIRTUAL_ENV={envdir}
          PYTHONHASHSEED=0
          CHARM_DIR={envdir}
-install_command =
-  {toxinidir}/pip.sh install {opts} {packages}
 commands = stestr run --slowest {posargs}
 allowlist_externals =
     charmcraft
     rename.sh
-passenv = HOME TERM CS_* OS_* TEST_*
+passenv =
+    HOME
+    TERM
+    CS_*
+    OS_*
+    TEST_*
 deps = -r{toxinidir}/test-requirements.txt
 
 [testenv:build]
@@ -77,7 +73,7 @@ commands = stestr run --slowest {posargs}
 [testenv:pep8]
 basepython = python3
 deps = flake8==3.9.2
-       charm-tools==2.8.3
+       charm-tools
 commands = flake8 {posargs} hooks unit_tests tests actions lib files
            charm-proof