Small refactory on Batch Type Definition

 to reflect the possibility of using a
 array with a single item (sql query)
 as an item of the batch, like:

 ['QUERY']

 The previous declaration will force something like
 ['QUERY', undefined]

Author: EduFrazao

src/index.ts

@@ -38,7 +38,7 @@ interface QueryResult {
  * If a single query must be executed many times with different arguments, its preferred
  * to declare it a single time, and use an array of array parameters.
  */
- type SQLBatchParams = [string, Array<any> | Array<Array<any>> | undefined];
+ type SQLBatchParams = [string] | [string, Array<any> | Array<Array<any>>];
 
 /**
  * status: 0 or undefined for correct execution, 1 for error