minor KnpLabs#1090 Create authorization removed from docs (rafasashi)

This PR was squashed before being merged into the 3.9.x-dev branch.

Discussion
----------

Create authorization deprecated and removed in V3 ([2fe12b8](KnpLabs@2fe12b8))

Commits
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92e683a Create authorization removed
cbac8bf Delete two_factor_authentication.md

Author: rafasashi

doc/authorizations.md

@@ -15,18 +15,6 @@ $authorizations = $github->api('authorizations')->all();
 $authorization = $github->api('authorizations')->show(1);
 ```
 
-#### Create an authorization
-
-```php
-$data = array(
-    'note' => 'This is an optional description'
-);
-
-$authorization = $github->api('authorizations')->create($data);
-```
-
-Creates and returns an authorization.
-
 #### Update an authorization
 
 You can update ``note``.