Update README with new YouTube URL.

Author: gregturn

README.adoc

@@ -24,7 +24,7 @@ He is a committer to Spring HATEOAS, Spring Data, Spring Boot, R2DBC, and Spring
 He also wrote Packt's best-selling title, _Learning Spring Boot 2.0 2nd Edition_.
 He co-founded the Nashville Java User Group in 2010 and hasn't met a Java app (yet) that he doesn't like.
 
-Follow him on Twitter @gregturn and subscribe for all his Spring Boot videos at https://www.youtube.com/user/gregturnquist?sub_confirmation=1&via=tb[YouTube.com/GregTurnquist].
+Follow him on Twitter @gregturn and subscribe for all his Spring Boot videos at https://www.youtube.com/SpringBootLearning?sub_confirmation=1&via=tb[YouTube.com/SpringBootLearning].
 
 == Code for the book
 
@@ -40,4 +40,4 @@ The code in this project is licensed http://apache.org/licenses/LICENSE-2.0.txt[
 
 == Contributions
 
-Please read the related link:CONTRIBUTING.adoc[CONTRIBUTING] document if you are interested in making contributions.
+Please read the related link:CONTRIBUTING.adoc[CONTRIBUTING] document if you are interested in making contributions.