Bugfix: Change 'units' type from int to str in TCTrackerTimeMetadata

[jatkinson1000]

Fixes #142

[jatkinson1000]

Have cf-python dropped support for Python 3.10?
There was a new release yesterday, but I can't see it explicitly stated.

[sjavis]

No, it doesn't seem to have been, and python 3.10 is not yet end of life. So it seems to be a bug in the new release.

I would suggest restricting to cf-python<3.19 for now.

[sjavis]

This is missed by the type checker because of a lack of type annotations in cftime. I would suggest adding a return type of TCTrackerTimeMetadata to example_time_metadata to at least ensure there is some type checking going on.

[jatkinson1000]

This is missed by the type checker because of a lack of type annotations in cftime. I would suggest adding a return type of TCTrackerTimeMetadata to example_time_metadata to at least ensure there is some type checking going on.

Done in 1480093

[jatkinson1000]

Rebased to pick up version and linting fixes from main.