fix: examples/fabric-contract-example-maven/pom.xml to reduce vulnerabilities (#469)

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-CHQOSLOGBACK-13169722

Signed-off-by: snyk-bot <[email protected]>

Author: jwagantall

examples/fabric-contract-example-maven/pom.xml

@@ -15,7 +15,7 @@
 		<fabric-chaincode-java.version>2.5.6</fabric-chaincode-java.version>
 
 		<!-- Logging -->
-		<logback.version>1.5.18</logback.version>
+		<logback.version>1.5.19</logback.version>
 		<slf4j.version>2.0.17</slf4j.version>
 
 		<!-- Test -->