fix: log4shell-goof/log4shell-server/pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-ORGAPACHELOGGINGLOG4J-14532782

Author: snyk-bot

log4shell-goof/log4shell-server/pom.xml

@@ -20,7 +20,7 @@
     <dependency>
       <groupId>org.apache.logging.log4j</groupId>
       <artifactId>log4j-core</artifactId>
-      <version>2.15.0</version>
+      <version>2.25.3</version>
     </dependency>
     <dependency>
       <groupId>com.unboundid</groupId>