mypy test is failing

[Linchin]

The mypy nox session has been failing starting yesterday:

The error log is as follows:

nox > Running session mypy
nox > Creating virtual environment (virtualenv) using python3.8 in .nox/mypy
nox > python -m pip install -e '.[all]'
nox > python -m pip install mypy==0.910
nox > python -m pip install types-protobuf types-python-dateutil types-requests types-setuptools
nox > mypy google/cloud
/tmpfs/src/github/python-bigquery/.nox/mypy/lib/python3.8/site-packages/jupyter_client/manager.py: error: INTERNAL ERROR -- Please try using mypy master on Github:
[https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build](https://www.google.com/url?q=https://mypy.readthedocs.io/en/stable/common_issues.html%23using-a-development-mypy-build&sa=D)
If this issue continues with mypy master, please report a bug at [https://github.com/python/mypy/issues](https://www.google.com/url?q=https://github.com/python/mypy/issues&sa=D)
version: 0.910
/tmpfs/src/github/python-bigquery/.nox/mypy/lib/python3.8/site-packages/jupyter_client/manager.py: : note: please use --show-traceback to print a traceback when reporting a bug
nox > Command mypy google/cloud failed with exit code 2
nox > Session mypy failed.**

Because currently we are using mypy==0.910, while the latest version is at 1.6.1, it's likely that an upgrade will fix this issue.