ci: bump actions/upload-artifact from 5 to 6 (#64)

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/tests.yml

@@ -38,7 +38,7 @@ jobs:
 
       - name: Upload bottles as artifact
         if: always() && github.event_name == 'pull_request'
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: bottles_${{ matrix.os }}
           path: '*.bottle.*'