Bump logback-core from 1.2.3 to 1.2.9

Bumps logback-core from 1.2.3 to 1.2.9.

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

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/pom.xml b/pom.xml
index 58f1375..13ec326 100644
--- a/pom.xml
+++ b/pom.xml
@@ -207,7 +207,7 @@
     <gson.version>2.2.4</gson.version>
     <guava.version>13.0.1</guava.version>
     <guice.version>3.0</guice.version>
-    <logback.version>1.2.3</logback.version>
+    <logback.version>1.2.9</logback.version>
     <hadoop.version>2.2.0</hadoop.version>
     <hbase11.version>1.1.1</hbase11.version>
     <hbase12cdh.version>1.2.0-cdh5.7.0</hbase12cdh.version>