Don't explicitly derive from object in Python (#1552)

That's an artifact from Python 2, Python 3 does that automatically.

uniffi_bindgen/src/bindings/python/templates/EnumTemplate.py

@@ -19,7 +19,7 @@ def __init__(self):
 
  # Each enum variant is a nested class of the enum itself.
  {% for variant in e.variants() -%}
- class {{ variant.name()|enum_variant_py }}(object):
+ class {{ variant.name()|enum_variant_py }}:
  def __init__(self,{% for field in variant.fields() %}{{ field.name()|var_name }}{% if loop.last %}{% else %}, {% endif %}{% endfor %}):
  {% if variant.has_fields() %}
  {%- for field in variant.fields() %}

uniffi_bindgen/src/bindings/python/templates/ObjectTemplate.py

@@ -1,6 +1,6 @@
 {%- let obj = ci.get_object_definition(name).unwrap() %}
 
-class {{ type_name }}(object):
+class {{ type_name }}:
  {%- match obj.primary_constructor() %}
  {%- when Some with (cons) %}
  def __init__(self, {% call py::arg_list_decl(cons) -%}):

uniffi_bindgen/src/bindings/python/templates/RustBufferTemplate.py

@@ -75,7 +75,7 @@ def __str__(self):
  return "ForeignBytes(len={}, data={})".format(self.len, self.data[0:self.len])
 
 
-class RustBufferStream(object):
+class RustBufferStream:
  """
  Helper for structured reading of bytes from a RustBuffer
  """
@@ -140,7 +140,7 @@ def readDouble(self):
  def readCSizeT(self):
  return self._unpack_from(ctypes.sizeof(ctypes.c_size_t) , "@N")
 
-class RustBufferBuilder(object):
+class RustBufferBuilder:
  """
  Helper for structured writing of bytes into a RustBuffer.
  """