Fix manylinux-2010 build

[nph4rd]

Description

Currently, our publishing workflow with the quay.io/pypa/manylinux2010_x86_64 container is failing with:

pip: command not found

I think this change ought to fix it.

Affected Dependencies

No.

How has this been tested?

Ran the commands in the container

Checklist

• [x] I have followed the Contribution Guidelines and Code of Conduct
• [x] I have commented my code following the OpenMined Styleguide
• [x] I have labeled this PR with the relevant Type labels
• [x] My changes are covered by tests