Bump version to 5.0.0 and update changelog

Updated plugin version to 5.0.0 in indieweb.php and readme.md. Added changelog for 5.0.0 release, highlighting PHP 7.4+ requirement, WordPress 6.9 compatibility, refreshed icons, improved security, and code quality enhancements.

Author: pfefferle

indieweb.php

@@ -5,7 +5,7 @@
  * Description: Interested in connecting your WordPress site to the IndieWeb?
  * Author: IndieWebCamp WordPress Outreach Club
  * Author URI: https://indieweb.org/WordPress_Outreach_Club
- * Version: 4.0.5
+ * Version: 5.0.0
  * License: MIT
  * License URI: http://opensource.org/licenses/MIT
  * Text Domain: indieweb

readme.md

@@ -6,7 +6,7 @@
 - Requires at least: 4.7
 - Requires PHP: 7.4
 - Tested up to: 6.9
-- Stable tag: 4.0.5
+- Stable tag: 5.0.0
 - License: MIT
 - License URI: http://opensource.org/licenses/MIT
 
@@ -80,6 +80,13 @@ One could certainly download, install, and activate some or all of these plugins
 
 Project maintained on github at [indieweb/wordpress-indieweb](https://github.com/indieweb/wordpress-indieweb).
 
+### 5.0.0
+* Requires PHP 7.4 or higher
+* Tested with WordPress 6.9
+* Refreshed icons
+* Improved security with better input sanitization and output escaping
+* Improved code quality and plugin structure
+
 ### 4.0.5
 * Update dependencies
 * Update assets