Update README.md

Corrected a verb form

Author: lalitshankarch

README.md

@@ -53,4 +53,4 @@ at your option.
 
 Unless you explicitly state otherwise, any contribution intentionally submitted
 for inclusion in Rust by Example by you, as defined in the Apache-2.0 license, shall be
-dual licensed as above, without any additional terms or conditions.
+dually licensed as above, without any additional terms or conditions.