Update pip3 to 18.x on Ubuntu 18.04 LTS

Check for python3 version:

# python3
Python 3.6.7 (default, Oct 22 2018, 11:32:17)
[GCC 8.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>

Install pip3:

# wget https://bootstrap.pypa.io/get-pip.py
# python3 get-pip.py

Check pip3:

# pip3
-bash: /usr/bin/pip3: No such file or directory

but:

# pip -V
pip 18.1 from /usr/local/lib/python3.6/dist-packages/pip (python 3.6)

pip === pip3 ??! Make a symblink for it:

# ln -s /usr/local/bin/pip /usr/bin/pip3
# pip3 -V
pip 18.1 from /usr/local/lib/python3.6/dist-packages/pip (python 3.6)