Temporarily disable starters

The build fails on CI with:

```
Error:  Failed to execute goal on project spring-shell-starter-test: Could not resolve dependencies for project org.springframework.shell:spring-shell-starter-test:pom:4.0.0-SNAPSHOT: Could not find artifact org.springframework.shell:spring-shell-starter:jar:4.0.0-SNAPSHOT -> [Help 1]
```

even though it passes locally in a fresh docker container.

Author: fmbenhassine

pom.xml

@@ -77,7 +77,7 @@
 		<module>spring-shell-docs</module>
 		<module>spring-shell-dependencies</module>
 		<module>spring-shell-samples</module>
-		<module>spring-shell-starters</module>
+<!--		<module>spring-shell-starters</module>--> <!-- FIXME build failure on CI -->
 	</modules>
 
 	<build>