fix: Install pip and pip-tools in upgrade script

[edx-requirements-bot]

Additional information from script execution

Python code cleanup by the cleanup-python-code Jenkins job.

This pull request was generated by the cleanup-python-code Jenkins job, which ran

``` echo "# Core dependencies for installing other packages pip-tools setuptools wheel " >> requirements/pip.in; pip-compile --allow-unsafe --rebuild --upgrade -o requirements/pip.txt requirements/pip.in; ```

The following packages were installed: pip-tools

Deleted obsolete pull_requests: https://github.com/edx/edx-e2e-tests/pull/538

[edx-requirements-bot]

Closing obsolete PR.