FIX: Force pip version to fix build

The following error seems to be caused by
a mismatch in pip versions. It looks similar
to: pypa/pip#5373

kpnnv/katka-core make publish
"python3.8" setup_gen.py
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/pkgversion/pkgversion.py", line 8, in <module>
    from pip._internal.download import PipSession
ModuleNotFoundError: No module named 'pip._internal.download'

To prevent this from happening, we upgrade to the
newest pip.

Makefile

@@ -142,6 +142,7 @@ setup.py:
 	@echo 'setup.py created'
 
 publish: setup.py
+	$(PIP) install -U pip
 	$(PYTHON) setup.py sdist bdist_wheel
 	$(TWINE) check dist/*
 	$(TWINE) upload dist/*