Update release notes, version number and date

Author: martignoni

CHANGELOG.md

@@ -3,7 +3,7 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](https://semver.org/) and follow principles of [keep a changelog](https://keepachangelog.com).
 
-## Version 2.16.0, unreleased
+## Version 2.16.0, 2023-07-30
 
 ### Add
 - Enable displaying date and time buttons in the footer of any page for users with adequate role (issue #94).

version.php

@@ -26,9 +26,9 @@
 
 $plugin = new stdClass();
 
-$plugin->version  = 2023071700;
-$plugin->release = '2.16.0-beta';
+$plugin->version  = 2023073000;
+$plugin->release = '2.16.0';
 $plugin->requires = 2018120300;
 $plugin->supported = [36, 420];
-$plugin->maturity = MATURITY_BETA;
+$plugin->maturity = MATURITY_STABLE;
 $plugin->component = 'tool_moodlebox';