Update builtin pip

[vQuadX]

We have an error, that fixed in new version of pip
File "/Users/user/venv/lib/python3.9/site-packages/pur/packages/pip/_internal/utils/logging.py", line 81, in indent_log _log_state.indentation += num
pypa/pip#2977

And old version of pip Version object don't have major, minor, micro properties.

Please update builtin pip
Why we use builtin pip instead of pip as requirement?

[alanhamlett]

Fixed with #43.