Update README.md

README.md

@@ -96,7 +96,7 @@ If you want the results to be written to this directory (not to a new directory)
 OUTDIR: /path/to/outdir
 ```
 ### Error Optparse
-if you get an error about R package optparse. Enter the R environment by writing R and clicking enter. Install the packages:
+If you get an error about R package optparse. Enter the R environment by writing R and clicking enter. Install the packages:
 `install.packages("optparse")`
 
 ## RESULTS