except unicode in is_datetime64_dtype

is_datetime64_dtype is trying to check the type
of unicodes but numpy does not support unicode and
this line breaks.

Add except error and return false
Test for unicode still fails for python 2

Author: Nikoleta-v3

pandas/core/dtypes/common.py

@@ -394,6 +394,8 @@ def is_datetime64_dtype(arr_or_dtype):
         tipo = _get_dtype_type(arr_or_dtype)
     except TypeError:
         return False
+    except UnicodeEncodeError:
+        return False
     return issubclass(tipo, np.datetime64)