Fix tox4 error

tox.ini started failing with Tox4 which had some
incompatible changes. One of them is to allow
external command to run by adding them into allowlist_externals

Fixing tox.ini for tox4 changes.

Change-Id: I7bc7c98954395765f16cc943e5c826983db5dba0

tox.ini

@@ -1,6 +1,5 @@
 [tox]
 minversion = 3.2.0
-skipsdist = True
 envlist = validate,py3,pep8,pip-install
 ignore_basepython_conflict=true
 
@@ -14,11 +13,15 @@ commands =
   stestr run {posargs}
 
 [testenv:py38-check-uc]
+allowlist_externals =
+  check-conflicts
 basepython = python3.8
 deps = -r{toxinidir}/upper-constraints.txt
 commands = check-conflicts {toxinidir}/upper-constraints.txt {toxinidir}/upper-constraints-xfails.txt
 
 [testenv:py39-check-uc]
+allowlist_externals =
+  check-conflicts
 basepython = python3.9
 deps = -r{toxinidir}/upper-constraints.txt
 commands = check-conflicts {toxinidir}/upper-constraints.txt {toxinidir}/upper-constraints-xfails.txt
@@ -27,9 +30,13 @@ commands = check-conflicts {toxinidir}/upper-constraints.txt {toxinidir}/upper-c
 commands = {posargs}
 
 [testenv:update]
+allowlist_externals =
+  update-requirements
 commands = update-requirements {posargs}
 
 [testenv:generate]
+allowlist_externals =
+  generate-constraints
 description = Regenerates upper-constraints.txt
 # Generate needs an unconstrained install to get new dependencies
 deps = -r{toxinidir}/requirements.txt
@@ -37,17 +44,29 @@ deps = -r{toxinidir}/requirements.txt
 commands = generate-constraints {posargs: -b blacklist.txt -r global-requirements.txt -p python3.6 -p python3.7 -p python3.8 -p python3.9 -p python3.10 > upper-constraints.txt}
 
 [testenv:validate]
+allowlist_externals =
+  validate-constraints
 commands =
     validate-constraints {toxinidir}/global-requirements.txt {toxinidir}/upper-constraints.txt {toxinidir}/blacklist.txt
 
 [testenv:validate-projects]
+allowlist_externals =
+  validate-projects
 commands = validate-projects {toxinidir}/projects.txt
 
 # TODO remove once zuul reconfigured to run linters on gate
 [testenv:pep8]
 deps = {[testenv:linters]deps}
-whitelist_externals = {[testenv:linters]whitelist_externals}
-commands = {[testenv:linters]commands}
+allowlist_externals =
+  bash
+commands =
+    flake8
+    bash -c "find {toxinidir}/tools      \
+                 -type f                 \
+                 -name \*.sh             \
+                 -print0 | xargs -0 bashate -v -iE006,E010"
+    bash -c 'sed -e "s,===,==," upper-constraints.txt > {envtmpdir}/safety-check.txt'
+    -safety check --json -r {envtmpdir}/safety-check.txt
 
 [testenv:linters]
 description = Perform linting
@@ -55,7 +74,8 @@ deps =
     hacking>=1.0.0
     bashate>=0.5.1
     safety
-whitelist_externals = bash
+allowlist_externals =
+  bash
 commands =
     flake8
     bash -c "find {toxinidir}/tools      \
@@ -77,6 +97,8 @@ commands = bindep test
 usedevelop = False
 
 [testenv:docs]
+allowlist_externals =
+  sphinx-build
 deps = -c{env:TOX_CONSTRAINTS_FILE:{toxinidir}/upper-constraints.txt}
        -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html
@@ -87,12 +109,16 @@ deps = .
 commands = python {toxinidir}/tools/check-install.py
 
 [testenv:requirements-check]
+allowlist_externals =
+  {toxinidir}/playbooks/files/project-requirements-change.py
 deps = -r{toxinidir}/requirements.txt
 commands =
   {toxinidir}/playbooks/files/project-requirements-change.py --local {posargs}
 
 [testenv:babel]
 # Use the local upper-constraints.txt file
+allowlist_externals =
+  {toxinidir}/tools/babel-test.sh
 deps = Babel
 commands = {toxinidir}/tools/babel-test.sh