fix sanitizeHex regex check to check $color (#52)

Author: mikemunger

src/Mexitek/PHPColors/Color.php

@@ -528,7 +528,7 @@ private static function sanitizeHex(string $hex): string
         $color = str_replace("#", "", $hex);
 
         // Validate hex string
-        if (!preg_match('/^[a-fA-F0-9]+$/', $hex)) {
+        if (!preg_match('/^[a-fA-F0-9]+$/', $color)) {
             throw new Exception("HEX color does not match format");
         }
 

tests/colorInput.phpt

@@ -0,0 +1,19 @@
+<?php
+
+require __DIR__ . '/bootstrap.php';
+
+use Mexitek\PHPColors\Color;
+use Tester\Assert;
+
+// Test that a hex starting with '#' is supported as input
+$expected = array(
+    "#ffffff",
+    "#00ff00",
+    "#000000",
+    "#ff9a00",
+);
+
+foreach ($expected as $input) {
+    $color = new Color($input);
+    Assert::same((string) $color, $input, 'Incorrect color returned.');
+}