Add maxBatchSize dataloader config support

Author: mikoarce

src/config.ts

@@ -28,6 +28,7 @@ export interface BatchResourceConfig {
     isBatchKeyASet?: boolean;
     propertyBatchKey?: string;
     responseKey?: string;
+    maxBatchSize?: number;
 }
 
 export interface NonBatchResourceConfig {

src/implementation.ts

@@ -514,7 +514,8 @@ function getPropertyBatchLoader(resourceConfig: BatchResourceConfig, resourcePat
                   * flow errors :(
                   */ ''
              }
-             ...cacheKeyOptions
+             ...cacheKeyOptions,
+            ${resourceConfig.maxBatchSize ? `maxBatchSize: ${resourceConfig.maxBatchSize},` : ''}
          }
      )`;
 }