deps: python 3.10 for docs

Required to get myst-parser up to v4

.github/workflows/continuous-integration.yml

@@ -88,7 +88,7 @@ jobs:
         with:
           miniforge-variant: Mambaforge
           miniforge-version: latest
-          python-version: 3.9
+          python-version: "3.10"
           use-mamba: true
           channel-priority: strict
           environment-file: ./docs/environment.yml
@@ -139,7 +139,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: 3.9
+          python-version: "3.10"
       - name: Download uv
         run: curl -LsSf https://astral.sh/uv/install.sh | sh
       - name: Install geos

docs/environment.yml

@@ -6,7 +6,7 @@ dependencies:
   - cartopy
   - geos
   - pandoc
-  - python=3.9
+  - python=3.10
   - pip
   - pip:
       - -e ../[docs]