Reconfigure tox.ini

Update minversion of tox to 3.9.0 to support inline comments [1]

Move pep8 and coverage requirements to tox.ini

Fix typo in coverage job

[1] https://tox.readthedocs.io/en/latest/changelog.html#v3-9-0-2019-04-17

Change-Id: I3f39b25ee0fd44c1bc51f94a7fbee74de8cba65d

test-requirements.txt

@@ -2,10 +2,5 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-hacking>=3.1.0,<4.0.0 # Apache-2.0
-
 stestr>=1.0.0 # Apache-2.0
 coverage!=4.4,>=4.0 # Apache-2.0
-flake8-import-order>=0.17.1 # LGPLv3
-pycodestyle>=2.0.0,<2.7.0 # MIT
-

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-minversion = 3.2.1
+minversion = 3.9.0
 envlist = pep8
 skipsdist = True
 ignore_basepython_conflict=true
@@ -15,6 +15,10 @@ deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/up
 commands = stestr run --slowest {posargs}
 
 [testenv:pep8]
+deps =
+    hacking>=3.1.0,<4.0.0 # Apache-2.0
+    flake8-import-order>=0.17.1 # LGPLv3
+    pycodestyle>=2.0.0,<2.7.0 # MIT
 commands = flake8 {posargs}
 
 [testenv:venv]
@@ -27,7 +31,7 @@ setenv =
 commands =
     stestr run {posargs}
     coverage combine
-    coverage htlm -d cover
+    coverage html -d cover
     coverage xml -o cover/coverage.xml
 
 [testenv:docs]