Fixup Python dep

Author: tautschnig

.github/workflows/kani.yml

@@ -156,6 +156,12 @@ jobs:
         with:
           submodules: true
 
+      # The Kani metrics collection uses a Python script (kani_std_analysis.py), so make sure Python is installed
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: '3.x'
+
       # Step 2: Run list on the std library
       - name: Run Kani Metrics
         run: |