Use fixed version of python

Author: grasci-arm

.github/workflows/projmgr.yml

@@ -132,6 +132,10 @@ jobs:
         with:
           submodules: true
 
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
+        with:
+          python-version: '3.13.3'
+
       - name: Build swig python libs
         if: matrix.pyswig
         uses: Open-CMSIS-Pack/devtools-build-action@1f131b70796337c98d4f680632bb4135d90f17f0 # arm64