fix: samples/virtualan-openapi-mongo/pom.xml to reduce vulnerabilities (#465)

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-COMFASTERXMLJACKSONCORE-3038424

Co-authored-by: snyk-bot <[email protected]>

Author: elans3

samples/virtualan-openapi-mongo/pom.xml

@@ -143,7 +143,7 @@
 		<dependency>
 			<groupId>com.fasterxml.jackson.core</groupId>
 			<artifactId>jackson-databind</artifactId>
-			<version>2.13.2.1</version>
+			<version>2.13.4</version>
 		</dependency>