Updating version to release

Author: Albertoimpl

README.adoc

@@ -1,6 +1,6 @@
 = Spring Cloud Gateway and gRPC
 
-Starting from `3.1.0-RC1`, Spring Cloud Gateway included support for gRPC and HTTP/2.
+Starting from `3.1.0`, Spring Cloud Gateway included support for gRPC and HTTP/2.
 
 We will introduce the basic concepts behind gRPC and how to configure it with two examples:
 
@@ -237,4 +237,4 @@ We see how the gateway application forwards the requests and returns the JSON pa
 == Next Steps
 
 In this post, we've looked at a few examples of how gRPC can be integrated within Spring Cloud Gateway. I’d love to know
-what other usages you've found to be helpful in your experiences.
+what other usages you've found to be helpful in your experiences.