Update to spring-io-plugin:0.0.8.RELEASE

Fixes gh-8271

build.gradle

@@ -6,7 +6,7 @@ buildscript {
 	dependencies {
 		classpath "com.github.ben-manes:gradle-versions-plugin:0.17.0"
 		classpath("org.springframework.build.gradle:propdeps-plugin:0.0.7")
-		classpath("io.spring.gradle:spring-io-plugin:0.0.6.RELEASE")
+		classpath("io.spring.gradle:spring-io-plugin:0.0.8.RELEASE")
 		classpath("com.bmuschko:gradle-tomcat-plugin:2.2.4")
 		classpath('me.champeau.gradle:gradle-javadoc-hotfix-plugin:0.1')
 		classpath('org.asciidoctor:asciidoctor-gradle-plugin:1.5.1')