tests: cache sample files

Author: henryborchers

.github/workflows/tox_matrix.yml

@@ -48,11 +48,11 @@ jobs:
         id: cache_samples
         uses: actions/cache@v4
         with:
-          path: "${{ github.workspace }}"
+          path: "${{ github.workspace }}/sampledata/"
           key: sample-images
       - name: download sample files
         if: steps.cache_samples.outputs.cache-hit != 'true'
-        run: curl -L https://nexus.library.illinois.edu/repository/sample-data/images/sample_images.tar.gz -o "${{ github.workspace }}/sample_images.tar.gz"
+        run: curl -L https://nexus.library.illinois.edu/repository/sample-data/images/sample_images.tar.gz --create-dirs -o "${{ github.workspace }}/sampledata/sample_images.tar.gz"
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}