Replace use of numpy aliases of built-in types with built-in type

Numpy 1.20 deprecated the use of numpy aliases of built-in types. 
Replacing the aliases with the built-in types does not change behavior 
but will silence the deprecation warning. 
https://numpy.org/devdocs/release/1.20.0-notes.html#deprecations

Author: rly

datajoint/blob.py

@@ -164,7 +164,7 @@ def pack_blob(self, obj):
             return self.pack_recarray(np.array(obj))
         if isinstance(obj, np.number):
             return self.pack_array(np.array(obj))
-        if isinstance(obj, (np.bool, np.bool_)):
+        if isinstance(obj, (bool, np.bool_)):
             return self.pack_array(np.array(obj))
         if isinstance(obj, (datetime.datetime, datetime.date, datetime.time)):
             return self.pack_datetime(obj)
@@ -365,7 +365,7 @@ def read_struct(self):
         raw_data = [
             tuple(self.read_blob(n_bytes=int(self.read_value('uint64'))) for _ in range(n_fields))
             for __ in range(n_elem)]
-        data = np.array(raw_data, dtype=list(zip(field_names, repeat(np.object))))
+        data = np.array(raw_data, dtype=list(zip(field_names, repeat(object))))
         return self.squeeze(data.reshape(shape, order="F"), convert_to_scalar=False).view(MatStruct)
 
     def pack_struct(self, array):

datajoint/table.py

@@ -586,7 +586,7 @@ def _update(self, attrname, value=None):
             value = blob.pack(value)
             placeholder = '%s'
         elif attr.numeric:
-            if value is None or np.isnan(np.float(value)):  # nans are turned into NULLs
+            if value is None or np.isnan(float(value)):  # nans are turned into NULLs
                 placeholder = 'NULL'
                 value = None
             else:
@@ -615,7 +615,7 @@ def __make_placeholder(self, name, value, ignore_extra_fields=False):
         attr = self.heading[name]
         if attr.adapter:
             value = attr.adapter.put(value)
-        if value is None or (attr.numeric and (value == '' or np.isnan(np.float(value)))):
+        if value is None or (attr.numeric and (value == '' or np.isnan(float(value)))):
             # set default value
             placeholder, value = 'DEFAULT', None
         else:  # not NULL