pyright above 1.1.308 has failures on our tests

[Dr-Irv]

See microsoft/pyright#5178

Using the released version from https://github.com/pandas-dev/pandas-stubs/releases/tag/v2.0.1.230501

• Version 1.1.308 reported zero errors
• Version 1.1.309 reported 171 errors
• Version 1.1.310 reported 36 errors

Until microsoft/pyright#5178 is resolved, need to keep pyright at 1.1.308. There is the possibility that the newer versions are picking up real issues with our stubs that we need to address, but I'm doubtful.

We may see people using pyright in VS Code reporting issues that are pyright bugs, not our bugs.