disable mypy run for Python 3.10

[svlandeg]

Description

Until mypy 0.980 is released with this fix, we're disabling the mypy tests on the CI for Python 3.10.

Types of change

hot fix to CI infrastructure

Checklist

• I confirm that I have the right to submit this contribution under the project's MIT license.
• I ran the tests, and all new and existing tests passed.
• My changes don't require a change to the documentation, or if they do, I've added all required information.