Stop testing on Python 3.8

In production we are running on Python 3.7 and 3.9 (soon also to be
running on 3.11) so speed up tests by not running them on Python 3.8.

.github/workflows/build-and-test.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: [3.7, 3.8, 3.9]
+        python-version: [3.7, 3.9]
 
     steps:
       - uses: actions/checkout@v3

tests/docker/Dockerfile

@@ -18,7 +18,6 @@ RUN add-apt-repository ppa:deadsnakes/ppa && \
     apt-get -y install --no-install-recommends \
       curl git build-essential \
       python3.7-dbg python3.7-dev python3.7-distutils \
-      python3.8-dbg python3.8-dev \
       python3.9-dbg python3.9-dev \
       python3-pip
 

tox.ini

@@ -6,7 +6,7 @@
 # When changing the python or django version also change it in the tox example
 # of the documentation in hacking.rst
 [tox]
-envlist = {unit,integration,functional}-py{37,38,39}-django{32}, javascript, docs
+envlist = {unit,integration,functional}-py{37,39}-django{32}, javascript, docs
 skipsdist = True
 basepython = python3.7
 
@@ -18,7 +18,6 @@ markers =
 [gh-actions]
 python =
     3.7: py37
-    3.8: py38
     3.9: py39
 
 [testenv]