Support for Django 5.0 and python 3.12 + Fix CI (#277)

* Upgrade to last Django & Python supported versions

* flake8 fixes

* Add CI

* Add final version of Django 5.0

.github/workflows/main.yml

@@ -0,0 +1,40 @@
+name: CI
+
+on:
+  push:
+    branches:
+    - main
+  pull_request:
+
+concurrency:
+  group: ${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  tests:
+    name: Python ${{ matrix.python-version }}
+    runs-on: ubuntu-22.04
+
+    strategy:
+      matrix:
+        python-version:
+        - '3.8'
+        - '3.9'
+        - '3.10'
+        - '3.11'
+        - '3.12'
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip setuptools wheel
+        python -m pip install --upgrade 'tox>=4.0.0rc3'
+
+    - name: Run tox targets for ${{ matrix.python-version }}
+      run: tox run -f py$(echo ${{ matrix.python-version }} | tr -d .)