Update dependency nebula.lint to v20.6.0

Author: renovate[bot]

gradle/libs.versions.toml

@@ -4,7 +4,7 @@ sonarqube = '6.2.0.5505'
 jacocolog = '3.1.0'
 spotbugs = '6.1.12'
 ben-manes-versions = '0.52.0'
-nebula-lint = '20.5.8'
+nebula-lint = '20.6.0'
 jgitver = '0.10.0-rc03'
 gradleup-shadow = '9.0.0-beta15'