feat: invalidate cache when srcset config changes

Author: timnarr

classes/Imagex.php

@@ -159,7 +159,7 @@ private function getDynamicSrcsetPreset(string|null $ratio = null, File|null $im
 		// Cache settings
 		$version = $this->kirby->plugin('timnarr/imagex')->version();
 		$cache = $this->kirby->cache('timnarr.imagex');
-		$cacheKey = implode('-', [$version, $ratioX, $ratioY, $this->srcsetName]);
+		$cacheKey = implode('-', [$version, $ratioX, $ratioY, json_encode($srcsetPreset)]);
 		$cacheId = 'srcset-config-' . hash('xxh3', $cacheKey);
 
 		// Get srcsetPreset from cache or set it