Fix copy in README

(cherry picked from commit d4bf221)

Author: mikfreedman

README.adoc

@@ -61,7 +61,7 @@ Having trouble with Spring Boot, We'd like to help!
 * Check the {docs}/htmlsingle/[reference documentation], especially the
   {docs}/htmlsingle/#howto[How-to's] -- they provide solutions to the most common
   questions.
-* Learn the Spring basics -- Spring Boot is builds on many other Spring projects, check
+* Learn the Spring basics -- Spring Boot builds on many other Spring projects, check
   the http://spring.io[spring.io] web-site for a wealth of reference documentation. If
   you are just starting out with Spring, try one of the http://spring.io/guides[guides].
 * Ask a questions - we monitor http://stackoverflow.com[stackoverflow.com] for questions