Bump ch.qos.logback:logback-classic in the dependencies group

Bumps the dependencies group with 1 update: [ch.qos.logback:logback-classic](https://github.com/qos-ch/logback).


Updates `ch.qos.logback:logback-classic` from 1.5.20 to 1.5.21
- [Release notes](https://github.com/qos-ch/logback/releases)
- [Commits](qos-ch/logback@v_1.5.20...v_1.5.21)

---
updated-dependencies:
- dependency-name: ch.qos.logback:logback-classic
  dependency-version: 1.5.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dependencies
...

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

Author: dependabot[bot]

tests/test-client-generation/pom.xml

@@ -26,7 +26,7 @@
     <dependency>
       <groupId>ch.qos.logback</groupId>
       <artifactId>logback-classic</artifactId>
-      <version>1.5.20</version>
+      <version>1.5.21</version>
     </dependency>
 
     <dependency>