fix a bug which caused v1 cred backwards-compat to apply to v2 requests

see: https://github.com/ansible/ansible-tower/issues/7793

awx/api/serializers.py

@@ -2127,7 +2127,7 @@ class CredentialSerializer(BaseSerializer):
 
     def to_internal_value(self, data):
         # TODO: remove when API v1 is removed
-        if 'credential_type' not in data:
+        if 'credential_type' not in data and self.version == 1:
             # If `credential_type` is not provided, assume the payload is a
             # v1 credential payload that specifies a `kind` and a flat list
             # of field values

awx/main/tests/functional/api/test_credential.py

@@ -588,7 +588,7 @@ def test_create_org_credential_as_admin(post, organization, org_admin, credentia
     params['name'] = 'Some name'
     params['organization'] = organization.id
     response = post(
-        reverse('api:credential_list'),
+        reverse('api:credential_list', kwargs={'version': version}),
         params,
         org_admin
     )
@@ -604,7 +604,7 @@ def test_credential_detail(post, get, organization, org_admin, credentialtype_ss
     params['name'] = 'Some name'
     params['organization'] = organization.id
     response = post(
-        reverse('api:credential_list'),
+        reverse('api:credential_list', kwargs={'version': version}),
         params,
         org_admin
     )
@@ -1467,6 +1467,14 @@ def test_credential_type_mutability(patch, organization, admin, credentialtype_s
                 'as it may break the functionality of the resources using it.']
     assert response.data['credential_type'] == expected
 
+    response = patch(
+        reverse('api:credential_detail', kwargs={'version': 'v2', 'pk': cred.pk}),
+        {'name': 'Worst credential ever'},
+        admin
+    )
+    assert response.status_code == 200
+    assert Credential.objects.get(pk=cred.pk).name == 'Worst credential ever'
+
     related_obj.delete()
     response = _change_credential_type()
     assert response.status_code == 200