fix: Adjust Base64 converter

Author: HofmeisterAn

src/Docker.DotNet/Base64Converter.cs

@@ -4,14 +4,13 @@ internal class Base64Converter : JsonConverter<IList<byte>>
 {
     public override IList<byte> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
     {
-        var base64 = reader.GetString();
-        return base64 == null ? null : Encoding.UTF8.GetBytes(base64);
+        var base64String = reader.GetString();
+        return base64String == null ? null : Convert.FromBase64String(base64String);
     }
 
     public override void Write(Utf8JsonWriter writer, IList<byte> value, JsonSerializerOptions options)
     {
-        // TODO: This seams not correct, it breaks: 'SwarmConfig_CanCreateAndRead'.
-        var base64 = Encoding.UTF8.GetString(value.ToArray());
-        writer.WriteStringValue(base64);
+        var base64String = Convert.ToBase64String(value.ToArray());
+        writer.WriteStringValue(base64String);
     }
 }

src/Docker.DotNet/TimeSpanNanoSecondsConverter.cs

@@ -6,9 +6,9 @@ internal class TimeSpanNanosecondsConverter : JsonConverter<TimeSpan>
 
     public override TimeSpan Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
     {
-        var valueInNanoSeconds = reader.GetInt64();
-        var milliSecondValue = valueInNanoSeconds / MilliSecondToNanoSecond;
-        return TimeSpan.FromMilliseconds(milliSecondValue);
+        var valueInNanoseconds = reader.GetInt64();
+        var valueInMilliseconds = valueInNanoseconds / MilliSecondToNanoSecond;
+        return TimeSpan.FromMilliseconds(valueInMilliseconds);
     }
 
     public override void Write(Utf8JsonWriter writer, TimeSpan timeSpan, JsonSerializerOptions options)