Excavator: Upgrades Baseline to the latest version (palantir#885)

Author: svc-excavator-bot

build.gradle

@@ -20,7 +20,7 @@ plugins {
     id 'com.gradle.plugin-publish' version '1.3.0'
 id 'com.palantir.git-version' version '3.1.0'
     id 'com.palantir.idea-test-fix' version '0.1.0'
- id 'com.palantir.baseline' version '6.8.0'
+ id 'com.palantir.baseline' version '6.9.0'
 id 'com.palantir.consistent-versions' version '2.31.0'
     id 'java-gradle-plugin'
     id 'groovy'