Update dependency ch.qos.logback:logback-classic to v1.5.21 (#19)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

pom.xml

@@ -48,7 +48,7 @@
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>
-            <version>1.5.20</version>
+            <version>1.5.21</version>
             <scope>test</scope>
         </dependency>
     </dependencies>