Add dependency management for 'ch.qos.logback:logback-classic'.

pom.xml

@@ -85,6 +85,7 @@
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<assertj.version>3.12.2</assertj.version>
 		<junit.version>4.12</junit.version>
+		<logback.version>1.2.3</logback.version>
 		<lombok.version>1.18.8</lombok.version>
 		<mockito.version>2.28.2</mockito.version>
 		<multithreadedtc.version>1.01</multithreadedtc.version>
@@ -128,6 +129,11 @@
 				<artifactId>multithreadedtc</artifactId>
 				<version>${multithreadedtc.version}</version>
 			</dependency>
+			<dependency>
+				<groupId>ch.qos.logback</groupId>
+				<artifactId>logback-classic</artifactId>
+				<version>${logback.version}</version>
+			</dependency>
 			<dependency>
 				<groupId>org.springframework.boot</groupId>
 				<artifactId>spring-boot-starter</artifactId>