[BUGFIX] Create Size with correct types in expandBackgroundShorthand (#814)

Co-authored-by: JakeQZ <jake.github@qzdesign.co.uk>

Author: oliverklee

config/phpstan-baseline.neon

@@ -6,9 +6,3 @@ parameters:
 			count: 2
 			path: ../src/OutputFormat.php
 
-		-
-			message: '#^Class Sabberworm\\CSS\\Value\\Size constructor invoked with 5 parameters, 1\-4 required\.$#'
-			identifier: arguments.count
-			count: 2
-			path: ../src/RuleSet/DeclarationBlock.php
-

src/RuleSet/DeclarationBlock.php

@@ -396,8 +396,8 @@ public function expandBackgroundShorthand(): void
             'background-repeat' => ['repeat'],
             'background-attachment' => ['scroll'],
             'background-position' => [
-                new Size(0, '%', null, false, $this->iLineNo),
-                new Size(0, '%', null, false, $this->iLineNo),
+                new Size(0, '%', false, $this->iLineNo),
+                new Size(0, '%', false, $this->iLineNo),
             ],
         ];
         $mRuleValue = $oRule->getValue();