fetch files sparse

Author: baszalmstra

.github/workflows/rattler-build.yml

@@ -1,3 +1,5 @@
+name: rattler-build
+
 on:
   pull_request: 
     branches: main
@@ -20,6 +22,11 @@ jobs:
           - { target: osx-64, host: macos-latest }
 
     steps:
+      - uses: actions/checkout@v4
+        with:
+          sparse-checkout: |
+            recipes
+            !recipes/example
       - name: Generate rattler-build URL
         shell: bash
         id: url