Bump logback-classic from 1.2.3 to 1.2.6

Bumps logback-classic from 1.2.3 to 1.2.6.

---
updated-dependencies:
- dependency-name: ch.qos.logback:logback-classic
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

pom.xml

@@ -133,7 +133,7 @@
       <dependency>
         <groupId>ch.qos.logback</groupId>
         <artifactId>logback-classic</artifactId>
-        <version>1.2.3</version>
+        <version>1.2.6</version>
         <scope>test</scope>
       </dependency>