Update README.md

I forgot to write in README.md about adding new functions.

Author: riderius

README.md

@@ -28,4 +28,6 @@ Python 3.8 or higher is recommended for using this program. You need to install
 3. Copying
 4. Moving
 5. Renaming
-6. Removing
+6. Removing
+7. Reading a file
+8. File overwrite