chore: regens API reference docs (#889)

diff --git a/docs/dyn/people_v1.contactGroups.members.html b/docs/dyn/people_v1.contactGroups.members.html
index 346a106..34df3d7 100644
--- a/docs/dyn/people_v1.contactGroups.members.html
+++ b/docs/dyn/people_v1.contactGroups.members.html
@@ -75,31 +75,31 @@
 <h1><a href="people_v1.html">People API</a> . <a href="people_v1.contactGroups.html">contactGroups</a> . <a href="people_v1.contactGroups.members.html">members</a></h1>
 <h2>Instance Methods</h2>
 <p class="toc_element">
-  <code><a href="#modify">modify(resourceName, body, x__xgafv=None)</a></code></p>
+  <code><a href="#modify">modify(resourceName, body=None, x__xgafv=None)</a></code></p>
 <p class="firstline">Modify the members of a contact group owned by the authenticated user.</p>
 <h3>Method Details</h3>
 <div class="method">
-    <code class="details" id="modify">modify(resourceName, body, x__xgafv=None)</code>
+    <code class="details" id="modify">modify(resourceName, body=None, x__xgafv=None)</code>
   <pre>Modify the members of a contact group owned by the authenticated user.
-<br>
+
 The only system contact groups that can have members added are
 `contactGroups/myContacts` and `contactGroups/starred`. Other system
 contact groups are deprecated and can only have contacts removed.
 
 Args:
-  resourceName: string, The resource name of the contact group to modify. (required)
-  body: object, The request body. (required)
+  resourceName: string, Required. The resource name of the contact group to modify. (required)
+  body: object, The request body.
     The object takes the form of:
 
 { # A request to modify an existing contact group's members. Contacts can be
       # removed from any group but they can only be added to a user group or
       # "myContacts" or "starred" system groups.
-    "resourceNamesToRemove": [ # The resource names of the contact people to remove in the form of in the
-        # form of `people/`<var>person_id</var>.
+    "resourceNamesToRemove": [ # Optional. The resource names of the contact people to remove in the form of
+        # `people/{person_id}`.
       "A String",
     ],
-    "resourceNamesToAdd": [ # The resource names of the contact people to add in the form of in the form
-        # `people/`<var>person_id</var>.
+    "resourceNamesToAdd": [ # Optional. The resource names of the contact people to add in the form of
+        # `people/{person_id}`.
       "A String",
     ],
   }
@@ -113,6 +113,10 @@
   An object of the form:
 
     { # The response to a modify contact group members request.
+    "canNotRemoveLastContactGroupResourceNames": [ # The contact people resource names that cannot be removed from their
+        # last contact group.
+      "A String",
+    ],
     "notFoundResourceNames": [ # The contact people resource names that were not found.
       "A String",
     ],