Update logback-classic to 1.5.6 (#1224)

## About this PR
📦 Updates
[ch.qos.logback:logback-classic](https://github.com/qos-ch/logback) from
`1.5.5` to `1.5.6`

## Usage
✅ **Please merge!**

I'll automatically update this PR to resolve conflicts as long as you
don't change it yourself.

If you'd like to skip this version, you can just close this PR. If you
have any feedback, just mention me in the comments below.

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<details>
<summary>⚙ Adjust future updates</summary>

Add this to your `.scala-steward.conf` file to ignore future updates of
this dependency:
```
updates.ignore = [ { groupId = "ch.qos.logback", artifactId = "logback-classic" } ]
```
Or, add this to slow down future updates of this dependency:
```
dependencyOverrides = [{
  pullRequests = { frequency = "30 days" },
  dependency = { groupId = "ch.qos.logback", artifactId = "logback-classic" }
}]
```
</details>

<sup>
labels: library-update, early-semver-patch, semver-spec-patch,
commit-count:1
</sup>

Co-authored-by: zio-scala-steward[bot] <145262613+zio-scala-steward[bot]@users.noreply.github.com>

build.sbt

@@ -15,7 +15,7 @@ lazy val kafkaVersion         = "3.7.0"
 lazy val embeddedKafkaVersion = "3.7.0" // Should be the same as kafkaVersion, except for the patch part
 
 lazy val kafkaClients = "org.apache.kafka" % "kafka-clients"   % kafkaVersion
-lazy val logback      = "ch.qos.logback"   % "logback-classic" % "1.5.5"
+lazy val logback      = "ch.qos.logback"   % "logback-classic" % "1.5.6"
 
 enablePlugins(ZioSbtEcosystemPlugin, ZioSbtCiPlugin)