Fix CI: install pcpp cxxheaderparser without -U to avoid setuptools upgrade incompatibility

Co-authored-by: mballance <1340805+mballance@users.noreply.github.com>

Author: Copilot

.github/workflows/ci.yml

@@ -15,7 +15,8 @@ jobs:
         python3 -m venv py
         ./py/bin/pip install -U ivpm
         ./py/bin/python3 -m ivpm update -a
-        ./packages/python/bin/pip install -U typing_extensions build pcpp cxxheaderparser
+        ./packages/python/bin/pip install -U typing_extensions build
+        ./packages/python/bin/pip install pcpp cxxheaderparser
         ./packages/python/bin/python3 setup.py build_ext --inplace
         ./packages/python/bin/python3 -m build -n
         ls src