Update dependency com.github.loki4j:loki-logback-appender to v1.6.0

Author: renovate[bot]

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

@@ -32,7 +32,7 @@
         <java.version>17</java.version>
         <commons-io.version>2.18.0</commons-io.version>
         <javax-servlet.version>6.1.0</javax-servlet.version>
-        <loki-logback.version>1.5.2</loki-logback.version>
+        <loki-logback.version>1.6.0</loki-logback.version>
         <spring.version>6.2.2</spring.version>
         <spring.boot.version>3.3.2</spring.boot.version>
         <slf4j.version>2.0.16</slf4j.version>