Update to org.bouncycastle:bcpkix-jdk15on 1.64

Fixes gh-7918

gradle/dependency-management.gradle

@@ -145,7 +145,7 @@ dependencyManagement {
 		dependency 'org.aspectj:aspectjweaver:1.9.5'
 		dependency 'org.assertj:assertj-core:3.11.1'
 		dependency 'org.attoparser:attoparser:2.0.4.RELEASE'
-		dependency 'org.bouncycastle:bcpkix-jdk15on:1.62'
+		dependency 'org.bouncycastle:bcpkix-jdk15on:1.64'
 		dependency 'org.bouncycastle:bcprov-jdk15on:1.58'
 		dependency 'org.codehaus.groovy:groovy-all:2.4.17'
 		dependency 'org.codehaus.groovy:groovy-json:2.4.17'