Set minimum Python version to 3.10, update dependencies

This is requirement imposed on us by reader, which requires Python 3.10
since version 3.9. However, now that Python 3.12 has been released, it's
good idea to bump minimum Python version anyway.

.github/workflows/cd.yml

@@ -21,7 +21,7 @@ jobs:
       - name: Set up default Python
         uses: actions/setup-python@v2
         with:
-          python-version: "3.9"
+          python-version: "3.10"
       - name: Install build tools
         run: python -m pip install poetry==${{ env.POETRY_VERSION}}
       - name: Install poetry export plugin

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Set up default Python
         uses: actions/setup-python@v2
         with:
-          python-version: "3.9"
+          python-version: "3.10"
       - name: Install build tools
         run: python -m pip install nox==${{ env.NOX_VERSION}} poetry==${{ env.POETRY_VERSION}}
       - name: Actually lint
@@ -30,7 +30,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.9", "3.10", "3.11"]
+        python-version: ["3.10", "3.11", "3.12"]
     steps:
       - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}

noxfile.py

@@ -15,7 +15,7 @@ def lint(session):
     )
 
 
-@nox.session(python=["3.9", "3.10", "3.11"])
+@nox.session(python=["3.10", "3.11", "3.12"])
 @nox.parametrize("django_ver", ["3.2.23", "4.1.13", "4.2.7"])
 def tests(session, django_ver):
     session.run(