chore: have actions run the remaining tox envs

tox.ini

@@ -10,10 +10,10 @@ envlist =
 
 [gh-actions]
 python =
-  3.12: py312-django50, py312-django51, py312-django51-jinja2
+  3.12: py312-django50, py312-django51, py312-django51-jinja2, coverage
   3.11: p311-django-51, p311-django-50, p311-django-50-jinjia, p311-django-42, p311-django-42-jinjia
   3.10: py310-django42, py310-django42-jinja2, py310-django50, py310-django51, py310-django50-jinja2
-  3.9: py39-django42, py39-django42-jinja2
+  3.9: py39-django42, py39-django42-jinja2, flake8, docs, gettext
 
 [testenv]
 changedir = testproject
@@ -53,7 +53,7 @@ commands = python -Wd manage.py test captcha --settings jinja2_settings
 
 
 [testenv:gettext]
-basepython = python3
+basepython = python3.9
 changedir = captcha/locale/
 allowlist_externals =
       msgfmt
@@ -80,12 +80,13 @@ commands =
       msgfmt -c -o zh_Hans/LC_MESSAGES/django.mo zh_Hans/LC_MESSAGES/django.po
 
 [testenv:flake8]
-basepython = python3.8
+basepython = python3.9
 deps = flake8==3.9.2
 commands=
     flake8 {toxinidir}/captcha
 
 [testenv:docs]
+basepython = python3.9
 deps =
         sphinx
         sphinx-book-theme