MDL-65759 library: Add patch moodle#115 for php-css-parser

Patch taken from MyIntervals/PHP-CSS-Parser#115 as specified in
moodle_readme.txt

Author: Chocolate-lightning

lib/php-css-parser/CSSList/CSSList.php

@@ -212,6 +212,20 @@ public function splice($iOffset, $iLength = null, $mReplacement = null) {
 		array_splice($this->aContents, $iOffset, $iLength, $mReplacement);
 	}
 
+    /**
+     * Insert an item before its sibling.
+     *
+     * @param mixed $oItem The item.
+     * @param mixed $oSibling The sibling.
+     */
+    public function insert($oItem, $oSibling) {
+        $iIndex = array_search($oSibling, $this->aContents);
+        if ($iIndex === false) {
+            return $this->append($oItem);
+        }
+        array_splice($this->aContents, $iIndex, 0, array($oItem));
+    }
+
 	/**
 	 * Removes an item from the CSS list.
 	 * @param RuleSet|Import|Charset|CSSList $oItemToRemove May be a RuleSet (most likely a DeclarationBlock), a Import, a Charset or another CSSList (most likely a MediaQuery)
@@ -314,7 +328,7 @@ public function render(\Sabberworm\CSS\OutputFormat $oOutputFormat) {
 
 		return $sResult;
 	}
-	
+
 	/**
 	* Return true if the list can not be further outdented. Only important when rendering.
 	*/

lib/php-css-parser/moodle_readme.txt

@@ -1,10 +1,7 @@
 PHP CSS Parser
 --------------
 
-Import git ref: c3b01ef0a85824e86fd86a74a8154d8d5c34b0ff
-                (master)
-
-Downloaded from: https://github.com/sabberworm/PHP-CSS-Parser
+Downloaded from: https://github.com/sabberworm/PHP-CSS-Parser/releases/tag/8.3.0
 
 Import procedure: