Bump ch.qos.logback:logback-classic from 1.5.20 to 1.5.21 (#733)

Bumps [ch.qos.logback:logback-classic](https://github.com/qos-ch/logback) 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
...

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

Author: dependabot[bot]

build.gradle

@@ -43,7 +43,7 @@ allprojects {
             testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine'
             testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
 
-            testImplementation 'ch.qos.logback:logback-classic:1.5.20'
+            testImplementation 'ch.qos.logback:logback-classic:1.5.21'
         }
 
         tasks.withType(Test).configureEach {