(maint) Fix YamlDotNet serializer

In the previous version of YamlDotNet, the Newline property of the
TextWriter was used to control whether a comment was included in the
output, however, this no longer seems to be respected in the latest
version of YamlDotNet.  Instead, make use of the WithNewLine method, and
conditionally set this based on when it is called.

Author: gep13

src/GitReleaseManager.Core/Configuration/ConfigSerializer.cs

@@ -36,12 +36,23 @@ public static Config Read(TextReader reader)
         }
 
         public static void Write(Config config, TextWriter writer)
+        {
+            Write(config, writer, newLine: string.Empty);
+        }
+
+        public static void Write(Config config, TextWriter writer, string newLine)
         {
             _logger.Debug("Starting serializing yaml configuration...");
             var serializerBuilder = new SerializerBuilder()
                 .WithTypeInspector(inner => new CommentGatheringTypeInspector(inner))
                 .WithEmissionPhaseObjectGraphVisitor(args => new CommentsObjectGraphVisitor(args.InnerVisitor))
                 .WithNamingConvention(HyphenatedNamingConvention.Instance);
+
+            if (!string.IsNullOrEmpty(newLine))
+            {
+                serializerBuilder = serializerBuilder.WithNewLine(newLine);
+            }
+
             var serializer = serializerBuilder.Build();
             serializer.Serialize(writer, config);
             _logger.Verbose("Successfully serialized configuration!");
@@ -67,11 +78,10 @@ public static void WriteSample(TextWriter writer)
             var configType = config.GetType();
 
             writer.Write("#");
-            writer.NewLine = Environment.NewLine + "#";
             SetConfigurationSamples(config, configType, writer);
 
             _logger.Verbose("Writing sample");
-            Write(config, writer);
+            Write(config, writer, newLine: Environment.NewLine + "#");
         }
 
         private static void SetConfigurationSamples(object config, Type configType, TextWriter writer)