phpcs: Always use long array syntax

Most of the code in RSS-Bridge uses the long array syntax.
This commit adds a check to enforce using this syntax over
the short array syntax.

All failures have been fixed.

bridges/PinterestBridge.php

@@ -30,7 +30,7 @@ class PinterestBridge extends FeedExpander {
 
 	private function fixLowRes() {
 
-		$newitems = [];
+		$newitems = array();
 		$pattern = '/https\:\/\/i\.pinimg\.com\/[a-zA-Z0-9]*x\//';
 		foreach($this->items as $item) {