feat: APCu caching driver: changelog, documentation

Author: sk757a

user_guide_src/source/changelogs/v4.7.0.rst

@@ -236,6 +236,7 @@ Libraries
 - **Cache:** Added ``persistent`` config item to Redis handler.
 - **Cache:** Added support for HTTP status in ``ResponseCache``.
 - **Cache:** Added ``Config\Cache::$cacheStatusCodes`` to control which HTTP status codes are allowed to be cached by the ``PageCache`` filter. Defaults to ``[]`` (all status codes for backward compatibility). Recommended value: ``[200]`` to only cache successful responses. See :ref:`Setting $cacheStatusCodes <web_page_caching_cache_status_codes>` for details.
+- **Cache:** Added `APCu <https://www.php.net/apcu>`_ caching driver.
 - **CURLRequest:** Added ``shareConnection`` config item to change default share connection.
 - **CURLRequest:** Added ``dns_cache_timeout`` option to change default DNS cache timeout.
 - **CURLRequest:** Added ``fresh_connect`` options to enable/disable request fresh connection.

user_guide_src/source/libraries/caching.rst

@@ -36,7 +36,7 @@ $handler
 ========
 
 The is the name of the handler that should be used as the primary handler when starting up the engine.
-Available names are: dummy, file, memcached, redis, predis, wincache.
+Available names are: apcu, dummy, file, memcached, redis, predis, wincache.
 
 $backupHandler
 ==============
@@ -273,6 +273,13 @@ Class Reference
 Drivers
 *******
 
+APCu Caching
+================
+
+APCu is an in-memory key-value store for PHP. 
+
+To use it, you need `APCu PHP extension <https://www.php.net/apcu>`_.
+
 File-based Caching
 ==================