chore: [DevOps] bump ch.qos.logback:logback-classic in the test group (#658)

Bumps the test 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:development
  update-type: version-update:semver-patch
  dependency-group: test
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

pom.xml

@@ -71,7 +71,7 @@
     <javaparser.version>3.27.1</javaparser.version>
     <jsonschema-generator.version>4.38.0</jsonschema-generator.version>
     <jackson.version>2.20.1</jackson.version>
-    <logback.version>1.5.20</logback.version>
+    <logback.version>1.5.21</logback.version>
     <!-- conflicts resolution -->
     <micrometer.version>1.16.0</micrometer.version>
     <json.version>20250517</json.version>

sample-code/spring-app/pom.xml

@@ -34,7 +34,7 @@
   <properties>
     <project.rootdir>${project.basedir}/../../</project.rootdir>
     <spring-boot.version>3.5.7</spring-boot.version>
-    <logback.version>1.5.20</logback.version>
+    <logback.version>1.5.21</logback.version>
     <cf-logging.version>4.0.0</cf-logging.version>
     <apache-tomcat-embed.version>11.0.13</apache-tomcat-embed.version>
     <!-- Skip end-to-end tests by default, can be overridden with -DskipTests=false -->