Update cmake-multi-platform.yml

Author: Avus-c

.github/workflows/cmake-multi-platform.yml

@@ -57,7 +57,9 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install spdx-tools
-        pyspdxtools -i ${{ github.workspace }}/example/output/*.spdx
+        # this has to create a parsing table for the spdx-file syntax, which for some reason
+        # is printed to stderr...
+        pyspdxtools -i ${{ github.workspace }}/example/output/*.spdx 2>&1
 
     - name: Configure CMake
       run: >