Bump logback-core from 1.0.9 to 1.2.9

Bumps logback-core from 1.0.9 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 61a5653..ed8936f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -142,7 +142,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <surefire.redirectTestOutputToFile>true</surefire.redirectTestOutputToFile>
         <slf4j.version>1.7.5</slf4j.version>
-        <logback.version>1.0.9</logback.version>
+        <logback.version>1.2.9</logback.version>
         <guava.version>13.0.1</guava.version>
         <gson.version>2.2.4</gson.version>
         <findbugs.jsr305.version>2.0.1</findbugs.jsr305.version>