Upgrade to Logback 1.1.3

Closes gh-2729

spring-boot-dependencies/pom.xml

@@ -87,7 +87,7 @@
 		<junit.version>4.11</junit.version>
 		<liquibase.version>3.0.8</liquibase.version>
 		<log4j.version>1.2.17</log4j.version>
-		<logback.version>1.1.2</logback.version>
+		<logback.version>1.1.3</logback.version>
 		<mockito.version>1.9.5</mockito.version>
 		<mongodb.version>2.12.5</mongodb.version>
 		<mysql.version>5.1.34</mysql.version>