Support for Pandas 3.0.0

[evertlammerts]

Related #37

Two small code fixes:

• Add support for native StringDType
• Fixes scope bug in lazy attribute reading in ConvertDateTimeTypes

Support for timedelta64[s|ms|us|ns]:

• Where Pandas used to only support timedelate64[ns], Pandas 3 now infers the resolution. We added support for reading all of the new types.
• We now output timedelta[us] whenever timedelatas are read from DuckDB, since that is DuckDB's own resolution. This is a breaking change.

Pyproject.toml updates:

• env markers to allow higher version of dependencies (pandas, pyarrow and adbc-driver-manager)

Lots of changes to tests:

• Removes the ArrowPandas and NumpyPandas helpers. We will now test using whatever default backend for almost all tests, which makes most sense for regular values.
• We do still test arrow dtypes, but we now do so explicitly.
• Support both zoneinfo.ZoneInfo objects (3.0.0 and up) and tzdata (before)

Also see:

• Migration Guide
• Changelog