feat: Improve UTC date string parsing in tests

Author: arturcic

src/GitVersion.Core.Tests/Formatting/DateFormatterTests.cs

@@ -22,7 +22,17 @@ public void TryFormat_NullValue_ReturnsFalse()
     [TestCase("2021-01-01T12:00:00Z", "yyyy-MM-ddTHH:mm:ssZ", "2021-01-01T12:00:00Z")]
     public void TryFormat_ValidDateFormats_ReturnsExpectedResult(string input, string format, string expected)
     {
-        var date = DateTime.Parse(input, CultureInfo.InvariantCulture);
+        // For UTC datetime strings, parse as UTC to ensure consistent behavior across timezones
+        DateTime date;
+        if (input.EndsWith("Z"))
+        {
+            date = DateTime.Parse(input, CultureInfo.InvariantCulture, DateTimeStyles.AdjustToUniversal);
+        }
+        else
+        {
+            date = DateTime.Parse(input, CultureInfo.InvariantCulture);
+        }
+
         var sut = new DateFormatter();
         var result = sut.TryFormat(date, format, out var formatted);
         result.ShouldBeTrue();