Fix dirty copier status during version check (#16)

* fix: stash pixi files after copier install in the template version check CI

---------

Co-authored-by: Copilot <[email protected]>

Author: irm-codebase

.github/workflows/template-check-version.yml

@@ -25,9 +25,11 @@ jobs:
       - name: Setup pixi
         uses: prefix-dev/[email protected]
 
-      - name: Add copier
-        run: pixi add copier
-
+      - name: Add copier, install it, and stash to avoid 'dirty' copier warnings
+        run: |
+          pixi add copier
+          pixi install
+          git stash push -m "Stash pixi lock and toml" -- pixi.lock pixi.toml
       - name: Add dummy GitHub credentials
         run: |
           git config --global user.name Copier update