MAINT: Set requires-pixi in pixi.toml

We don't have to pin the pixi version in the workflow - compatability of
Pixi versions can be managed by Pixi itself.

Author: VeckoTheGecko

.github/workflows/ci.yaml

@@ -14,7 +14,6 @@ concurrency:
 
 env:
   FORCE_COLOR: 3
-  PIXI_VERSION: "v0.63.2"
 
 jobs:
   detect-ci-trigger:
@@ -43,14 +42,11 @@ jobs:
 
     outputs:
       cache-key: ${{ steps.pixi-lock.outputs.cache-key }}
-      pixi-version: ${{ steps.pixi-lock.outputs.pixi-version }}
 
     steps:
       - uses: actions/checkout@v6
       - uses: Parcels-code/pixi-lock/create-and-cache@9a2866f8258b87a3c616d5ad7d51c6cd853df78b
         id: pixi-lock
-        with:
-          pixi-version: ${{env.PIXI_VERSION}}
       - uses: actions/upload-artifact@v6
         with:
           name: pixi-lock

doc/contribute/contributing.rst

@@ -198,11 +198,8 @@ Xarray uses `Pixi <https://pixi.sh/latest/>`_ to manage development environments
 Before starting any development, you'll need to create an isolated xarray
 development environment:
 
-- `Install Pixi <https://pixi.sh/latest/installation/>`_ - preferably the same version as the one listed in our ``ci.yaml`` `file <https://github.com/pydata/xarray/blob/main/.github/workflows/ci.yaml>`_
-
-  - Some features in Pixi are in active development, and xarray depends on these features.
-    Using the same version results in the best dev experience.
-  - Instructions for installing specific versions of Pixi can be seen on the Pixi installation page.
+- `Install Pixi <https://pixi.sh/latest/installation/>`_
+  - Xarray uses some Pixi features that are in active development. You might be prompted to upgrade your Pixi version to contribute to Xarray (this is controlled by the ``requires-pixi`` field in ``pixi.toml``)
 - Make sure that you have :ref:`cloned the repository <contributing.dev_workflow>`
 - ``cd`` to the *xarray* source directory
 

pixi.toml

@@ -2,6 +2,7 @@
 preview = ["pixi-build"]
 channels = ["conda-forge", "nodefaults"]
 platforms = ["win-64", "linux-64", "osx-arm64"]
+requires-pixi = ">=0.63.2"
 
 [package]
 name = "xarray"