BUG:TypeError: Cannot interpret 'CategoricalDtype(categories=['no', 'yes'], ordered=False)' as a data type
I just upgraded all my python libraries, and now my previous code is started to fail.
I'm using blaze with pandas. Here is my method code
```
blaze.data(res)
```
res contains below data
```
             col1         age  ...                                           col31  year
0            yes    55-64  ...                                             NaN  2011
1             no    25-34  ...                                             NaN  2011
2             no    55-64  ...                                             NaN  2011
```
I'm using below dependencies
```
- python=3.6.11=h4d41432_2_cpython
- blaze=0.11.3=py36h4e06776_0
- pandas=1.0.5=py36h0573a6f_0
- numpy=1.19.1=py36h3849536_2
```
I'm getting the following error
```
  File "cytoolz/functoolz.pyx", line 667, in cytoolz.functoolz.pipe
  File "cytoolz/functoolz.pyx", line 642, in cytoolz.functoolz.c_pipe
  File "/home/ubuntu/miniconda/envs/my_env/lib/python3.6/site-packages/blaze/interactive.py", line 153, in data
    dshape = discover(data_source)
  File "/home/ubuntu/miniconda/envs/my_env/lib/python3.6/site-packages/multipledispatch/dispatcher.py", line 278, in __call__
    return func(*args, **kwargs)
  File "/home/ubuntu/miniconda/envs/my_env/lib/python3.6/site-packages/odo/backends/pandas.py", line 31, in discover_dataframe
    for k in df.columns])
  File "/home/ubuntu/miniconda/envs/my_env/lib/python3.6/site-packages/odo/backends/pandas.py", line 31, in <listcomp>
    for k in df.columns])
  File "/home/ubuntu/miniconda/envs/my_env/lib/python3.6/site-packages/odo/backends/pandas.py", line 23, in dshape_from_pandas
    dshape = datashape.CType.from_numpy_dtype(col.dtype)
  File "/home/ubuntu/miniconda/envs/my_env/lib/python3.6/site-packages/datashape/coretypes.py", line 779, in from_numpy_dtype
    if np.issubdtype(dt, np.datetime64):
  File "/home/ubuntu/miniconda/envs/my_env/lib/python3.6/site-packages/numpy/core/numerictypes.py", line 388, in issubdtype
    arg1 = dtype(arg1).type
TypeError: Cannot interpret 'CategoricalDtype(categories=['no', 'yes'], ordered=False)' as a data type
```

It's failing to parse second column values.