Update CHANGELOG for v2.2.0 release.

Author: markrogoyski

CHANGELOG.md

@@ -1,14 +1,9 @@
 # IterTools PHP Change Log
 
-## v2.2.0 - TBD
-
-### Improvements
-* Fix NaN handling in `Math::runningMax` and `Math::runningMin` to preserve monotonicity (skip NaN values and carry forward accumulator; yield NaN when no prior value exists)
-* Fix `Random::percentage` to always yield float (previously yielded int(0) when underlying RNG returned 0)
-* Upgrade Psalm from v6 to v7 for PHP 8.5 compatibility
+## v2.2.0 - 2026-04-19
 
 ### New Features
-* Combinatorics (new class)
+* Combinatorics (new)
   * `product`
   * `permutations`
   * `combinations`
@@ -39,6 +34,10 @@
   * `zipFilled`
   * `zipEqual`
 
+### Improvements
+* Fix NaN handling in `Math::runningMax` and `Math::runningMin` to preserve monotonicity (skip NaN values and carry forward accumulator; yield NaN when no prior value exists)
+* Fix `Random::percentage` to always yield float (previously yielded int(0) when underlying RNG returned 0)
+* Upgrade Psalm from v6 to v7 for PHP 8.5 compatibility
 
 ## v2.1.0 - 2026-03-29