Fix broken preload URL

[jsf9k]

🗣 Description

This pull request fixes a broken URL pointing to the Chromium HSTS preloaded domain list.

💭 Motivation and context

The location of this data has changed upstream, and this is breaking the BOD 18-01 scanning.

Required to resolve cisagov/scanner#67.

🧪 Testing

All automated testing that is expected to pass passes. The Python 3.6 tests fail because Python 3.6 is no longer supported by GitHub Actions.

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All new and existing tests pass.

✅ Pre-merge checklist

• Finalize version.

✅ Post-merge checklist

• Create a release.
• Push to PyPI.org.

[jsf9k]

Can we just drop support for Python 3.6? The 3.6 tests are failing because GitHub Actions no longer supports 3.6.

I can just ignore them for now.

[mcdonnnj]

We will drop Python 3.6 support when we update to a newer version of sslyze so I'd rather just leave that alone for now. Do you want to handle the release to PyPI or shall I?

[dav3r]

👍