Bump ch.qos.logback:logback-classic from 1.5.18 to 1.5.21

Bumps [ch.qos.logback:logback-classic](https://github.com/qos-ch/logback) from 1.5.18 to 1.5.21.
- [Release notes](https://github.com/qos-ch/logback/releases)
- [Commits](qos-ch/logback@v_1.5.18...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
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -16,5 +16,5 @@ jetbrains-annotations = { module = "org.jetbrains:annotations", version = "24.1.
 quark-eventbus = { module = "com.coditory.quark:quark-eventbus", version = "0.0.5" }
 # test dependencies
 spock-core = { module = "org.spockframework:spock-core", version = "2.4-M6-groovy-4.0" }
-logback-classic = { module = "ch.qos.logback:logback-classic", version = "1.5.18" }
+logback-classic = { module = "ch.qos.logback:logback-classic", version = "1.5.21" }
 jsonassert = { module = "org.skyscreamer:jsonassert", version = "1.5.3" }