Remove pin on pixi version

Author: VeckoTheGecko

.github/workflows/ci.yml

@@ -19,7 +19,6 @@ env:
   # Many color libraries just need this to be set to any value, but at least
   # one distinguishes color depth, where "3" -> "256-bit color".
   FORCE_COLOR: 3
-  PIXI_VERSION: "v0.63.2"
 
 jobs:
   cache-pixi-lock:
@@ -31,8 +30,6 @@ jobs:
       - uses: actions/checkout@v4
       - uses: Parcels-code/pixi-lock/create-and-cache@9a2866f8258b87a3c616d5ad7d51c6cd853df78b
         id: pixi-lock
-        with:
-          pixi-version: ${{env.PIXI_VERSION}}
       - uses: actions/upload-artifact@v6 # make available as an artifact for local testing
         with:
           name: pixi-lock