Use Python 3.12 for GitHub actions

For all GitHub Actions that do not use a version matrix to ensure
that the code itself works with older versions, use Python 3.12 as
the Python version, under the principle that tests unrelated to
compatibility should follow the latest supported Python version.

.github/workflows/ci.yaml

@@ -27,7 +27,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.11"
+          python-version: "3.12"
 
       - name: Run pre-commit
         uses: pre-commit/action@v3.0.1
@@ -68,7 +68,7 @@ jobs:
       - name: Run tox
         uses: lsst-sqre/run-tox@v1
         with:
-          python-version: "3.11"
+          python-version: "3.12"
           tox-envs: "docs,docs-linkcheck"
 
       # Only attempt documentation uploads for tagged releases and pull
@@ -101,7 +101,7 @@ jobs:
       - name: Build and publish
         uses: lsst-sqre/build-and-publish-to-pypi@v2
         with:
-          python-version: "3.11"
+          python-version: "3.12"
           upload: false
 
   pypi:
@@ -124,4 +124,4 @@ jobs:
 
       - uses: lsst-sqre/build-and-publish-to-pypi@v2
         with:
-          python-version: "3.11"
+          python-version: "3.12"

.github/workflows/periodic-ci.yaml

@@ -53,7 +53,7 @@ jobs:
       - name: Build docs in tox
         uses: lsst-sqre/run-tox@v1
         with:
-          python-version: "3.11"
+          python-version: "3.12"
           tox-envs: "docs,docs-linkcheck"
           use-cache: false
 
@@ -80,7 +80,7 @@ jobs:
       - name: Build and publish
         uses: lsst-sqre/build-and-publish-to-pypi@v2
         with:
-          python-version: "3.11"
+          python-version: "3.12"
           upload: false
 
       - name: Report status