updated README file, updated links to CakePHP documentation

CHANGELOG.md

@@ -2,7 +2,8 @@
 ## 2.13 branch
 ### 2.13.4
 * the `README` file has been updated for compatibility with older versions of CakePHP and PHP (branches have been
-    removed and older versions are available as tags).
+    removed and older versions are available as tags);
+* updated `README` file, updated links to CakePHP documentation.
 
 ### 2.13.3
 * added `--reverse` option for the `IndexCommand` ([issue #96](https://github.com/mirko-pagliai/cakephp-database-backup/issues/96));

README.md

@@ -38,7 +38,7 @@ $ composer require --prefer-dist mirko-pagliai/cakephp-database-backup
 ```
 
 Then you have to load the plugin. For more information on how to load the plugin,
-please refer to the [Cookbook](//book.cakephp.org/4.0/en/plugins.html#loading-a-plugin).
+please refer to the [Cookbook](https://book.cakephp.org/5/en/plugins.html#loading-a-plugin).
 
 Simply, you can execute the shell command to enable the plugin:
 ```bash
@@ -76,7 +76,7 @@ The plugin uses some configuration parameters. See our wiki:
 
 If you want to send backup files by email, remember to set up your application
 correctly so that it can send emails. For more information on how to configure
-your application, see the [Cookbook](https://book.cakephp.org/4.0/en/core-libraries/email.html#configuring-transports).
+your application, see the [Cookbook](https://book.cakephp.org/5/en/core-libraries/email.html#configuring-transports).
 
 ## How to use
 See our wiki: