Errors with pandas 2.0.

[lgautier]

Describe the issue or bug

Pandas 2.0 is the new major pandas release. It introduces API-breaking changes. The following rpy2 tests fail with pandas 2.0.

FAILED rpy2/tests/robjects/test_pandas_conversions.py::TestPandasConversions::test_series_issue264 - AttributeError: module 'pandas' has no attribute 'Int64Index'
FAILED rpy2/tests/robjects/test_pandas_conversions.py::TestPandasConversions::test_datetime2posixct - AttributeError: 'datetime.timezone' object has no attribute 'zone'
FAILED rpy2/tests/robjects/test_pandas_conversions.py::TestPandasConversions::test_datetime2posixct_withNA - AttributeError: 'datetime.timezone' object has no attribute 'zone'

To Reproduce

1. update pandas to the latest in the 2.0 series.
2. pytest rpy2/tests/robjects/test_pandas_conversions.py

Expected behavior

Tests passing without error.

Error

__________________ TestPandasConversions.test_series_issue264 __________________

self = <rpy2.tests.robjects.test_pandas_conversions.TestPandasConversions object at 0x7f91ff45b520>

    def test_series_issue264(self):
        Series = pandas.core.series.Series
        s = Series(('a', 'b', 'c', 'd', 'e'),
>                  index=pandas.Int64Index([0,1,2,3,4]))
E       AttributeError: module 'pandas' has no attribute 'Int64Index'

rpy2/tests/robjects/test_pandas_conversions.py:245: AttributeError
_________________ TestPandasConversions.test_datetime2posixct __________________

self = <rpy2.tests.robjects.test_pandas_conversions.TestPandasConversions object at 0x7f91ff485700>

    def test_datetime2posixct(self):
        datetime = pandas.Series(
            pandas.date_range('2017-01-01 00:00:00.234',
                              periods=20, freq='ms', tz='UTC')
        )
        with localconverter(default_converter + rpyp.converter) as cv:
>           rp_c = robjects.conversion.converter_ctx.get().py2rpy(datetime)

rpy2/tests/robjects/test_pandas_conversions.py:311: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/opt/hostedtoolcache/Python/3.8.16/x64/lib/python3.8/functools.py:875: in wrapper
    return dispatch(args[0].__class__)(*args, **kw)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

obj = 0    2017-01-01 00:00:00.234000+00:00
1    2017-01-01 00:00:00.235000+00:00
2    2017-01-01 00:00:00.236000+00:00
3   ...:00.251000+00:00
18   2017-01-01 00:00:00.252000+00:00
19   2017-01-01 00:00:00.253000+00:00
dtype: datetime64[ns, UTC]

    @py2rpy.register(pandas.core.series.Series)
    def py2rpy_pandasseries(obj):
        if obj.dtype.name == 'O':
            warnings.warn('Element "%s" is of dtype "O" and converted '
                          'to R vector of strings.' % obj.name)
            res = StrVector(obj)
        elif obj.dtype.name == 'category':
            res = py2rpy_categorical(obj.cat)
            res = FactorVector(res)
        elif is_datetime64_any_dtype(obj.dtype):
            # time series
>           tzname = obj.dt.tz.zone if obj.dt.tz else ''
E           AttributeError: 'datetime.timezone' object has no attribute 'zone'


rpy2/robjects/pandas2ri.py:179: AttributeError
______________ TestPandasConversions.test_datetime2posixct_withNA ______________

self = <rpy2.tests.robjects.test_pandas_conversions.TestPandasConversions object at 0x7f91ff485820>

    def test_datetime2posixct_withNA(self):
        datetime = pandas.Series(
            pandas.date_range('2017-01-01 00:00:00.234',
                              periods=20, freq='ms', tz='UTC')
        )
        datetime[1] = pandas.NaT
        with localconverter(default_converter + rpyp.converter) as cv:
>           rp_c = robjects.conversion.converter_ctx.get().py2rpy(datetime)

rpy2/tests/robjects/test_pandas_conversions.py:324: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/opt/hostedtoolcache/Python/3.8.16/x64/lib/python3.8/functools.py:875: in wrapper
    return dispatch(args[0].__class__)(*args, **kw)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

obj = 0    2017-01-01 00:00:00.234000+00:00
1                                 NaT
2    2017-01-01 00:00:00.236000+00:00
3   ...:00.251000+00:00
18   2017-01-01 00:00:00.252000+00:00
19   2017-01-01 00:00:00.253000+00:00
dtype: datetime64[ns, UTC]

    @py2rpy.register(pandas.core.series.Series)
    def py2rpy_pandasseries(obj):
        if obj.dtype.name == 'O':
            warnings.warn('Element "%s" is of dtype "O" and converted '
                          'to R vector of strings.' % obj.name)
            res = StrVector(obj)
        elif obj.dtype.name == 'category':
            res = py2rpy_categorical(obj.cat)
            res = FactorVector(res)
        elif is_datetime64_any_dtype(obj.dtype):
            # time series
>           tzname = obj.dt.tz.zone if obj.dt.tz else ''
E           AttributeError: 'datetime.timezone' object has no attribute 'zone'

rpy2/robjects/pandas2ri.py:179: AttributeError

Additional context

None.