BUG: Pandas doesn't build with Cython3.0 pre-release
This [line ](https://github.com/pandas-dev/pandas/blob/20569007ea256d3126214ab845190d08f88c73a9/pandas/_libs/reduction.pyx#L318):

```python
self.buf.data = self.values.data
```
will no longer build once Cython3.0 is released, due to this change: https://github.com/cython/cython/commit/22a49f403b6f00f1674664e01ee0f8212c06ef13#diff-24bcfc3298e43281fed97318a554550dL247.

`data` is no longer

```
ctypedef class numpy.ndarray [object PyArrayObject, check_size ignore]:
    ....
    char * data
```

but

```
ctypedef class numpy.ndarray [object PyArrayObject, check_size ignore]:
             ...
            @property
            cdef inline char* data(self) nogil:
                """The pointer to the data buffer as a char*.
                This is provided for legacy reasons to avoid direct struct field access.
                For new code that needs this access, you probably want to cast the result
                of `PyArray_DATA()` instead.
                """
                return PyArray_BYTES(self)
```

#### Error:

```
Error compiling Cython file:
    ------------------------------------------------------------
    ...
            self.buf.data = self.values.data    
    
    pandas\_libs\reduction.pyx:472:15: Assignment to a read-only property
```

#### Expected:

Should build.


