disallow duplicate method name

Author: itn3000

src/MicroBatchFramework/BatchEngineHostBuilderExtensions.cs

@@ -217,6 +217,10 @@ static List<Type> GetBatchTypes()
  {
  if (cmdattr.CommandNames.Any(x => arg0.Equals(x, StringComparison.OrdinalIgnoreCase)))
  {
+ if(foundType != null && foundMethod != null)
+ {
+ throw new InvalidOperationException($"Duplicate BatchBase Command name is not allowed, {foundType.FullName}.{foundMethod.Name} and {baseType.FullName}.{method.Name}");
+ }
  foundType = baseType;
  foundMethod = method;
  isFound = true;