chore: Python 3.12 is the floor, part A (#6)

The shared workflow tests on 3.12 and 3.13 by default and runs lowest on
3.12; the template declares requires-python >=3.12 with ruff and mypy on
3.12, and the tool itself needs 3.12. netOrk runs every driver on 3.12 in
its own containers.

check keeps accepting a 3.10 floor until every driver has moved; part B
raises it.

.gitea/workflows/driver.yml

@@ -24,7 +24,7 @@ on:
       python-versions:
         description: "JSON list of the Python versions the tests run on"
         type: string
-        default: '["3.10", "3.11", "3.12", "3.13"]'
+        default: '["3.12", "3.13"]'
       pypi-url:
         description: "Upload target; https://test.pypi.org/legacy/ for a dry run"
         type: string
@@ -123,7 +123,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.10"
+          python-version: "3.12"
       - name: Install the lowest versions the package allows
         run: |
           python -m venv .venv