build: fix typo in artifact name

Author: philipl

.github/workflows/unittests.yml

@@ -36,7 +36,7 @@ jobs:
       - name: Store artifacts
         uses: actions/upload-artifact@v4
         with:
-          name: python-package-distribution
+          name: python-package-distributions
           path: dist/
 
   publish-to-pypi:
@@ -80,7 +80,7 @@ jobs:
       - name: Download all the dists
         uses: actions/download-artifact@v4
         with:
-          name: python-package-distribution
+          name: python-package-distributions
           path: dist/
       - name: Publish distribution 📦 to TestPyPI
         uses: pypa/gh-action-pypi-publish@release/v1