Bump ch.qos.logback:logback-core from 1.0.9 to 1.3.15

Bumps [ch.qos.logback:logback-core](https://github.com/qos-ch/logback) from 1.0.9 to 1.3.15.
- [Commits](qos-ch/logback@v_1.0.9...v_1.3.15)

---
updated-dependencies:
- dependency-name: ch.qos.logback:logback-core
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pom.xml

@@ -31,7 +31,7 @@
 
     <cdap.version>6.4.1</cdap.version>
     <spark.version>2.1.3</spark.version>
-    <logback.version>1.0.9</logback.version>
+    <logback.version>1.3.15</logback.version>
     <cdap.plugin.version>2.6.1</cdap.plugin.version>
 
     <surefire.redirectTestOutputToFile>true</surefire.redirectTestOutputToFile>