Update requirements and changelog for 3.0.0 release

Raised minimum WordPress and PHP versions, updated stable tag to 3.0.0, and added changelog for major refactor, NodeInfo 2.2 support, new integration classes, PSR-4 autoloader, schema updates, protocol filter, and homepage field.

Author: pfefferle

README.md

@@ -3,10 +3,10 @@
 - Contributors: pfefferle
 - Donate link: https://notiz.blog/donate/
 - Tags: nodeinfo, fediverse, ostatus, diaspora, activitypub
-- Requires at least: 4.9
+- Requires at least: 6.6
 - Tested up to: 6.9
-- Stable tag: 2.3.1
-- Requires PHP: 5.6
+- Stable tag: 3.0.0
+- Requires PHP: 7.2
 - License: MIT
 - License URI: https://opensource.org/licenses/MIT
 
@@ -24,6 +24,16 @@ This plugin provides a barebone JSON file with basic "node"-informations. The fi
 
 Project and support maintained on github at [pfefferle/wordpress-nodeinfo](https://github.com/pfefferle/wordpress-nodeinfo).
 
+### 3.0.0
+
+* Refactored to filter-based architecture for better extensibility
+* Added support for NodeInfo 2.2
+* Added separate integration classes for each NodeInfo version (1.0, 1.1, 2.0, 2.1, 2.2)
+* Added PSR-4 style autoloader
+* Updated schemas to match official NodeInfo specifications with enums and constraints
+* Added `nodeinfo_protocols` filter for plugins to register protocols
+* Added `software.homepage` field for NodeInfo 2.1 and 2.2
+
 ### 2.3.1
 
 * mask version number