fix the grammar problem of the readme description

README.md

@@ -1,7 +1,7 @@
 # datasets-preprocessing-for-object-detection
 this repository includes some python parser scripts for converting other public datasets into voc data  format
 # note
-- I don't mean to provide the usage for this script, it's very simple to modified these files
+- I don't mean to provide the usage for these scripts, it's very simple to modified these files
 - most files in this repository are very similar, you can run for your own purpose
 # environment
 - python 3.5