ci: Add lower bound requirements tests

* Use 'uv pip install --upgrade --resolution lowest-direct' to
  automatically evaluate if the lower bounds of the dependencies
  specified are correct.

.github/workflows/lower-bound-requirements.yml

@@ -0,0 +1,36 @@
+name: Minimum supported dependencies
+
+on:
+  # Run weekly at 1:23 UTC
+  schedule:
+    - cron: "23 1 * * 0"
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+        # minimum supported Python
+        python-version: ["3.9"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies and force lowest bound
+        run: |
+          python -m pip install uv
+          uv pip install --system --upgrade ".[test]"
+          uv pip install --system --upgrade --resolution lowest-direct .
+
+      - name: List installed Python packages
+        run: uv pip list --system
+
+      - name: Test with pytest
+        run: pytest tests/