Update color test case for Mountain Meadow

The test case for color Mountain Meadow in ColorTest.php has been modified. The expected result of the RGBToHSL function was slightly incorrect and has now been updated for the accurate testing.

tests/ColorTest.php

@@ -82,7 +82,7 @@ public function testRGBToHSL(): void
 
         // Test case 6: Mountain Meadow
         $rgbColor = [17, 195, 128];
-        $expectedResult = [157, 0.87, 0.42];
+        $expectedResult = [157, 0.84, 0.42];
         $actualResult = Color::RGBToHSL($rgbColor[0], $rgbColor[1], $rgbColor[2]);
         $this->assertEquals($expectedResult, $actualResult, 'Case 6 failed: Mountain Meadow');