Fix the CorrectlyHandlesMultilineParameter unit test so it works both on Windows and Ubuntu

Author: Jericho

Source/HttpMultipartParser.UnitTests/HttpMultipartFormParserUnitTests.cs

@@ -67,8 +67,8 @@ line 3
             using (Stream stream = TestUtil.StringToStream(request, Encoding.UTF8))
             {
                 var parser = MultipartFormDataParser.Parse(stream, Encoding.UTF8);
-                Assert.Equal("line 1\r\nline 2\r\nline 3", parser.GetParameterValue("multilined"));
-                Assert.Equal("line 1\r\nline 2\r\nline 3", parser.GetParameterValues("multilined").First());
+                Assert.Equal($"line 1{Environment.NewLine}line 2{Environment.NewLine}line 3", parser.GetParameterValue("multilined"));
+                Assert.Equal($"line 1{Environment.NewLine}line 2{Environment.NewLine}line 3", parser.GetParameterValues("multilined").First());
             }
         }