CI: allow failure on mypy since lot of things are broken for now

9 jobs for branch/default in 1 minute and 54 seconds (queued for 12 seconds)
Name Stage Failure
mypy Tests
/builds/open-source/yams/.tox/mypy/bin/python -m pip install types-setuptools

Found 51 errors in 7 files (checked 13 source files)
ERROR: InvocationError for command /builds/open-source/yams/.tox/mypy/bin/mypy --install-types --non-interactive --ignore-missing-imports yams (exited with code 1)
___________________________________ summary ____________________________________
ERROR: mypy: commands failed
Cleaning up file based variables
ERROR: Job failed: command terminated with exit code 1