On the other hand, python package install description is using default python version pip.
When user environment default is python2, pip is used by python2 version.
In this case, python3 package will not be installed.
This patch modify to python package install description.
The tool is developed and tested only with Python 3. We do not plan to support Python 2. Pip instructions assume virtual environment created with Py3. Hence, no need for this update.
callgraph-tool.py implicitly use python3.
!/usr/bin/env python3
On the other hand, python package install description is using default python version pip. When user environment default is python2, pip is used by python2 version. In this case, python3 package will not be installed.
This patch modify to python package install description.