Update to okhttp 3.12.0

Fixes: gh-6166

gradle/dependency-management.gradle

@@ -6,7 +6,7 @@ dependencyManagement {
 	}
 	dependencies {
 		dependency 'cglib:cglib-nodep:3.2.9'
-		dependency 'com.squareup.okhttp3:mockwebserver:3.10.0'
+		dependency 'com.squareup.okhttp3:mockwebserver:3.12.0'
 		dependency 'opensymphony:sitemesh:2.4.2'
 		dependency 'org.gebish:geb-spock:0.10.0'
 		dependency 'org.jasig.cas:cas-server-webapp:4.2.7'
@@ -44,7 +44,7 @@ dependencyManagement {
 		dependency 'com.nimbusds:lang-tag:1.4.3'
 		dependency 'com.nimbusds:nimbus-jose-jwt:5.14'
 		dependency 'com.nimbusds:oauth2-oidc-sdk:5.64.4'
-		dependency 'com.squareup.okhttp3:okhttp:3.9.0'
+		dependency 'com.squareup.okhttp3:okhttp:3.12.0'
 		dependency 'com.squareup.okio:okio:1.13.0'
 		dependency 'com.sun.xml.bind:jaxb-core:2.3.0.1'
 		dependency 'com.sun.xml.bind:jaxb-impl:2.3.0.1'