BUG: pip install --upgrade pip in Dockerfile gets flagged

[duggalsu]

Describe the bug
Running RUN pip install --no-cache-dir --upgrade pip in a Dockerfile gets flagged with pipCommand not pinned by hash.

Expected behavior
The correct approach to doing pip install is to upgrade pip first, so this should ideally not be flagged.

[duggalsu]

Based on the following, it seems to be safe to pin pip and setuptool. I would suggest a good process would be to first update these as pinned packages from a base requirements.txt before doing any further pip install.

• Should --generate-hashes imply --allow-unsafe? jazzband/pip-tools#806
• Is it safe to pin setuptools/distribute/pip in requirements.txt? pypa/pip#6459

Closing issue as it does not seem relevant now