Update default and doc values for setApprovalPrompt. (googleapis#1535)

* Update default and doc values for setApprovalPrompt.

Author: mattwhisenhunt

src/Google/Client.php

@@ -125,7 +125,7 @@ public function __construct(array $config = array())
           'login_hint' => '',
           'request_visible_actions' => '',
           'access_type' => 'online',
-          'approval_prompt' => 'auto',
+          'approval_prompt' => 'consent',
 
           // Task Runner retry configuration
           // @see Google_Task_Runner
@@ -569,8 +569,9 @@ public function setAccessType($accessType)
 
   /**
    * @param string $approvalPrompt Possible values for approval_prompt include:
-   *  {@code "force"} to force the approval UI to appear.
-   *  {@code "auto"} to request auto-approval when possible. (This is the default value)
+   *  {@code "none"} Do not display any authentication or consent screens. Must not be specified with other values.
+   *  {@code "consent"} Prompt the user for consent.
+   *  {@code "select_account"} Prompt the user to select an account.
    */
   public function setApprovalPrompt($approvalPrompt)
   {

tests/Google/ClientTest.php

@@ -224,7 +224,7 @@ public function testPrepareService()
         . '&redirect_uri=http%3A%2F%2Flocalhost%2F'
         . '&state=xyz'
         . '&scope=http%3A%2F%2Ftest.com%20scope2'
-        . '&approval_prompt=auto',
+        . '&approval_prompt=consent',
 
         $client->createAuthUrl()
     );