fix some security issues reported by scorecard

[trz42]

• GHSA-3ww4-gg4f-jr7f fixed with cryptography >= 42.0.0, see https://osv.dev/vulnerability/GHSA-3ww4-gg4f-jr7f
• GHSA-9v9h-cgj8-h64p fixed with cryptography >= 42.0.2, see https://osv.dev/vulnerability/GHSA-9v9h-cgj8-h64p
• PYSEC-2021-62 / GHSA-hggm-jpg3-v476 fixed with either of the above changes
• PYSEC-2017-8 / GHSA-q3cj-2r34-2cwc fixed with either of the above changes
• GHSA-3f84-rpwh-47g6 fixed with waitress >= 3.0.1, see https://osv.dev/vulnerability/GHSA-3f84-rpwh-47g6
• GHSA-4f7p-27jc-3c36 fixed with the above
• GHSA-j7j6-7hfx-5522 fixed with the above
• GHSA-968f-66r5-5v74 fixed with the above
• GHSA-g2xc-35jw-c63p fixed with the above
• GHSA-m5ff-3wj3-8ph4 fixed with the above
• GHSA-pg36-wpm5-g57p fixed with the above
• PYSEC-2020-155 fixed with the above
• pinning versions of pytest and pytest-cov for tests CI
  • this also required pinning dependencies and creating a requirements-lock.txt file in the workflow directory

[ocaisa]

LGTM

[trz42]

LGTM

Sorry, still working on it.

[trz42]

Now, this should be ready for review. May not solve all issues, but should be a step forward.

[ocaisa]

Ha, smells like a workaround!