Update to spring-boot-gradle-plugin:1.5.22.RELEASE

Fixes gh-8262

build.gradle

@@ -11,7 +11,7 @@ buildscript {
 		classpath('me.champeau.gradle:gradle-javadoc-hotfix-plugin:0.1')
 		classpath('org.asciidoctor:asciidoctor-gradle-plugin:1.5.7')
 		classpath("io.spring.gradle:docbook-reference-plugin:0.3.1")
-		classpath("org.springframework.boot:spring-boot-gradle-plugin:1.5.19.RELEASE")
+		classpath("org.springframework.boot:spring-boot-gradle-plugin:1.5.22.RELEASE")
 		classpath "org.jfrog.buildinfo:build-info-extractor-gradle:4.12.0"
 		classpath 'org.hidetake:gradle-ssh-plugin:2.10.1'
 		classpath 'io.codearte.gradle.nexus:gradle-nexus-staging-plugin:0.10.0'