fix: use correct exports name

Signed-off-by: Pagebakers <eelco@appulse.nl>

Author: Pagebakers

packages/openapi-to-graphql/src/schema_builder.ts

@@ -36,7 +36,7 @@ import {
   GraphQLInputType,
   GraphQLInputFieldConfigMap
 } from 'graphql'
-import GraphQLUpload from 'graphql-upload/GraphQLUpload'
+import GraphQLUpload from 'graphql-upload/GraphQLUpload.js'
 
 // Imports:
 import { GraphQLBigInt, GraphQLJSON } from 'graphql-scalars'