use latest pip-tools (see securedrop-debian-packaging#248)

[sssoleileraaa]

Description

Rerun make update-pip-requirements with the latest pip-tools (see freedomofpress/securedrop-builder#248) so that we can retag 0.3.0 and push a new sdk release to pypi. Also fix bug on main when you delete .venv and rerun make venv:

Collecting pip>=20.0 (from pip-tools==5.3.1->-r dev-requirements.txt (line 149))
In --require-hashes mode, all requirements must have their versions pinned with ==. These do not:
    pip>=20.0 from https://files.pythonhosted.org/packages/7c/02/9ab8b431aca1b46fcc1ac830a5870a28a12ba1abfa681904b1d2da876a86/pip-21.2.1-py3-none-any.whl#sha256=da0ac9d9032d1d7bac69e9e301778f77b8b6626b85203f99edd2b545434d90a7 (from pip-tools==5.3.1->-r dev-requirements.txt (line 149))
make: *** [Makefile:7: venv] Error 1

[sssoleileraaa]

Test Plan

1. cd to your sdk project directory
2. rm -r .venv
3. make venv

• confirm no more require-hashes mode error around pinning pip-tools with >=

4. source .venv/bin/activate and run make update-pip-requirements

• confirm you are using the latest version of pip-compile and see no errors

[zenmonkeykstop]

Ran thru test plan, make update-pip-requirements completes successfully , but pip-tools version is 5.3.1, not latest.

[sssoleileraaa]

but pip-tools version is 5.3.1, not latest.

sry about that, pushed updated changes where it is pinned to 6.2.0 as expected

[zenmonkeykstop]

Test plan checks out, pip-tools at 6.2.0 (current latest)!