Bump logback-classic in /examples/fabric-contract-example-maven

Bumps logback-classic from 1.0.13 to 1.2.0.

---
updated-dependencies:
- dependency-name: ch.qos.logback:logback-classic
  dependency-type: direct:production
...

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

Author: dependabot[bot]

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

@@ -15,7 +15,7 @@
 		<fabric-chaincode-java.version>2.3.1</fabric-chaincode-java.version>
 
 		<!-- Logging -->
-		<logback.version>1.0.13</logback.version>
+		<logback.version>1.2.0</logback.version>
 		<slf4j.version>1.7.5</slf4j.version>
 
 		<!-- Test -->