v2.2.0

What's Changed

• feat: add to_json and as_json methods for JSON serialization by @cardmagic in #49
• feat: add to_hash and to_xml serialization methods by @cardmagic in #50
• feat: add URL fetching with conditional GET support by @cardmagic in #51
• feat: add Enumerable support and convenience accessors by @cardmagic in #52
• feat: add feed validation and search helpers by @cardmagic in #53
• feat: add feed merge and diff helpers by @cardmagic in #55
• feat: add media and enclosure helper APIs by @cardmagic in #54

Full Changelog: v2.0.0...v2.2.0