Update to python 3.12, pandas 2.1.2 (#713)

Part of #654
Fixes #645

I ran `pixi add pandas=2.1.2 python=3.12 pyogrio=0.7.2` using pixi
v0.5.0 so as not to update the lockfile format.

The new pyogrio release is needed to be able to use Python 3.12. We only
update the Python version in the Pixi lockfile and on CI, this does not
change our minimum supported Python version.

The pandas update to 2.1.2 fixes a regression present in 2.1.0 and
2.1.1, no further changes were needed in our code.

@Hofer-Julian I simply removed the `pandas < 2.1` restriction in the
pyproject.toml, assuming that is fine since with the release of pandas
2.1.2 most people won't get 2.1.0 or 2.1.1 anymore, though I guess we
could exclude multiple patch releases.

.github/workflows/pre-commit_auto_update.yml

@@ -16,7 +16,7 @@ jobs:
           ssh-key: ${{ secrets.SSH_PRIVATE_KEY }}
       - uses: actions/setup-python@v4
         with:
-          python-version: "3.11"
+          python-version: "3.12"
       - uses: browniebroke/pre-commit-autoupdate-action@main
       - uses: peter-evans/create-pull-request@v5
         with:

.github/workflows/pre-commit_check.yml

@@ -13,5 +13,5 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v4
         with:
-          python-version: "3.11"
+          python-version: "3.12"
       - uses: pre-commit/[email protected]