Change validation method to txt as in the CF API documentation + change response json file

tests/Endpoints/SSLTest.php

@@ -150,11 +150,11 @@ class SSLTest extends TestCase
             ->method('patch')
             ->with(
                 $this->equalTo('zones/c2547eb745079dac9320b638f5e225cf483cc5cfdda41/ssl/verification/a77f8bd7-3b47-46b4-a6f1-75cf98109948'),
-                $this->equalTo(['validation_method' => 'cname'])
+                $this->equalTo(['validation_method' => 'txt'])
             );
 
         $sslMock = new \Cloudflare\API\Endpoints\SSL($mock);
-        $result = $sslMock->updateSSLCertificatePackValidationMethod('c2547eb745079dac9320b638f5e225cf483cc5cfdda41', 'a77f8bd7-3b47-46b4-a6f1-75cf98109948', 'cname');
+        $result = $sslMock->updateSSLCertificatePackValidationMethod('c2547eb745079dac9320b638f5e225cf483cc5cfdda41', 'a77f8bd7-3b47-46b4-a6f1-75cf98109948', 'txt');
 
         $this->assertTrue($result);
     }

tests/Fixtures/Endpoints/updateSSLCertificatePackValidationMethod.json

@@ -2,5 +2,8 @@
   "success": true,
   "errors": [],
   "messages": [],
-  "result": "off"
+  "result": {
+    "validation_method": "txt",
+    "status": "pending_validation"
+  }
 }