Resolve version value in getting started guide

Author: fmbenhassine

spring-shell-docs/modules/ROOT/pages/getting-started.adoc

@@ -19,7 +19,7 @@ With _maven_ you're expected to have something like:
 [source, xml, subs=attributes+]
 ----
 <properties>
-    <spring-shell.version>LATEST_VERSION</spring-shell.version>
+    <spring-shell.version>{project-version}</spring-shell.version>
 </properties>
 
 <dependencies>
@@ -58,7 +58,7 @@ dependencies {
 
 dependencyManagement {
     imports {
-        mavenBom "org.springframework.shell:spring-shell-dependencies:LATEST_VERSION"
+        mavenBom "org.springframework.shell:spring-shell-dependencies:{project-version}"
     }
 }
 ----