Update pixelfed config, bump max_collection_length default to 100 from 18

config/pixelfed.php

@@ -239,7 +239,7 @@ return [
 		]
 	],
 
-	'max_collection_length' => (int) env('PF_MAX_COLLECTION_LENGTH', 18),
+	'max_collection_length' => (int) env('PF_MAX_COLLECTION_LENGTH', 100),
 
 	'media_types' => env('MEDIA_TYPES', 'image/jpeg,image/png,image/gif'),