Update snapshot repository documentation.

Closes gh-806

README.adoc

@@ -64,9 +64,9 @@ If you'd rather like the latest snapshots of the upcoming major version, use our
 </dependency>
 
 <repository>
-  <id>spring-libs-snapshot</id>
+  <id>spring-snapshot</id>
   <name>Spring Snapshot Repository</name>
-  <url>https://repo.spring.io/libs-snapshot</url>
+  <url>https://repo.spring.io/snapshot</url>
 </repository>
 ----
 ====

pom.xml

@@ -698,8 +698,8 @@
 
 			<repositories>
 				<repository>
-					<id>spring-libs-snapshot</id>
-					<url>https://repo.spring.io/libs-snapshot</url>
+					<id>spring-snapshot</id>
+					<url>https://repo.spring.io/snapshot</url>
 					<snapshots>
 						<enabled>true</enabled>
 					</snapshots>

src/main/asciidoc/reference/getting-started.adoc

@@ -60,7 +60,7 @@ Snapshot repository to your maven `pom.xml` which is at the same level of your `
   <repository>
     <id>spring-snapshot</id>
     <name>Spring Maven SNAPSHOT Repository</name>
-    <url>https://repo.spring.io/libs-snapshot</url>
+    <url>https://repo.spring.io/snapshot</url>
   </repository>
 </repositories>
 ----