Update dependency ch.qos.logback:logback-classic to v1.5.20 (#229)

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

Author: renovate[bot]

logstash-logging-spring-boot-starter/pom.xml

@@ -104,7 +104,7 @@
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>
-            <version>1.5.19</version>
+            <version>1.5.20</version>
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>

reactive-logstash-logging-spring-boot-starter/pom.xml

@@ -91,7 +91,7 @@
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>
-            <version>1.5.19</version>
+            <version>1.5.20</version>
         </dependency>
         <dependency>
             <groupId>io.projectreactor</groupId>