Update to okhttp3 3.9.0

Issue: gh-4608

gradle/dependency-management.gradle

@@ -6,7 +6,7 @@ dependencyManagement {
 	}
 	dependencies {
 		dependency 'cglib:cglib-nodep:3.2.5'
-		dependency 'com.squareup.okhttp3:mockwebserver:3.7.0'
+		dependency 'com.squareup.okhttp3:mockwebserver:3.9.0'
 		dependency 'opensymphony:sitemesh:2.4.2'
 		dependency 'org.gebish:geb-spock:0.10.0'
 		dependency 'org.jasig.cas:cas-server-webapp:4.0.0'
@@ -54,7 +54,7 @@ dependencyManagement {
 		dependency 'com.nimbusds:lang-tag:1.4.3'
 		dependency 'com.nimbusds:nimbus-jose-jwt:5.1'
 		dependency 'com.nimbusds:oauth2-oidc-sdk:5.38'
-		dependency 'com.squareup.okhttp3:okhttp:3.8.1'
+		dependency 'com.squareup.okhttp3:okhttp:3.9.0'
 		dependency 'com.squareup.okio:okio:1.13.0'
 		dependency 'com.vaadin.external.google:android-json:0.0.20131108.vaadin1'
 		dependency 'commons-cli:commons-cli:1.4'