Upgrade logback-classic to 1.2.8

http://mailman.qos.ch/pipermail/announce/2021/000164.html
https://jira.qos.ch/browse/LOGBACK-1591

Author: jsyrjala

CHANGELOG.md

@@ -3,6 +3,9 @@
 **Highlights**
 - `nflow-explorer`
   - Customizable workflow search result table columns
+- logback-classic update to version 1.2.8
+  - http://mailman.qos.ch/pipermail/announce/2021/000164.html
+  - https://jira.qos.ch/browse/LOGBACK-1591
 
 **Details**
 

pom.xml

@@ -131,7 +131,7 @@
     <junit4.version>4.13.1</junit4.version>
     <junit5.version>5.6.2</junit5.version>
     <lifecycle-mapping.version>1.0.0</lifecycle-mapping.version>
-    <logback-classic.version>1.2.3</logback-classic.version>
+    <logback-classic.version>1.2.8</logback-classic.version>
     <mariadb.version>2.7.1</mariadb.version>
     <maven-assembly.version>3.3.0</maven-assembly.version>
     <maven-asciidoctor.version>2.1.0</maven-asciidoctor.version>