Update dependency net.logstash.logback:logstash-logback-encoder to v9

Author: renovate[bot]

intro-to-spring-boot/pom.xml

@@ -47,7 +47,7 @@
         <dependency>
             <groupId>net.logstash.logback</groupId>
             <artifactId>logstash-logback-encoder</artifactId>
-            <version>8.1</version>
+            <version>9.0</version>
         </dependency>
 
         <dependency>