Tweaks to ci and mypy version

My local copy of mypy is complaining about things that ci is not, so this is an
attempt to ensure they use the same version (the latest, v1.16.0)

Author: trey-stafford

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
 
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.11"
+          python-version: "3.12"
 
       - name: Install package
         run: python -m pip install .[dev]

pyproject.toml

@@ -48,7 +48,7 @@ Changelog = "https://github.com/NSIDC/iceflow/releases"
 dev = [
   "bump-my-version",
   "invoke",
-  "mypy >=1.15.0",
+  "mypy >=1.16.0",
   "pandas-stubs >=2.2",
   "pre-commit",
   "pytest",