[en] fix the class name and the namespace.

[okinaka]

• Cake\Network\Request is renamed to Cake\Http\ServerRequest.
• Cake\Network\Response is renamed to Cake\Http\Response.
• Cake\Network\Http\Client is renamed to Cake\Http\Client.
• Cake\Network\Http\FormData is renamed to Cake\Http\Client\FormData.

[ravage84]

• https://api.cakephp.org/3.3/class-Cake.Network.Request.html => https://api.cakephp.org/3.5/class-Cake.Http.ServerRequest.html
• https://api.cakephp.org/3.3/class-Cake.Network.Response.html => https://api.cakephp.org/3.5/class-Cake.Http.Response.html
• https://api.cakephp.org/3.2/class-Cake.Network.Http.Client.html => https://api.cakephp.org/3.5/class-Cake.Http.Client.html
• https://api.cakephp.org/3.2/class-Cake.Network.Http.FormData.html => https://api.cakephp.org/3.5/class-Cake.Http.Client.FormData.html