Update java jwt and jwks (#62)

* Update java-jwt dependency

* Update jwks-rsa dependency

Author: poovamraj

lib/build.gradle

@@ -33,8 +33,8 @@ compileJava {
 ext.springSecurityVersion = '4.2.20.RELEASE'
 
 dependencies {
-    api "com.auth0:java-jwt:3.13.0"
-    api "com.auth0:jwks-rsa:0.15.0"
+    api "com.auth0:java-jwt:3.18.3"
+    api "com.auth0:jwks-rsa:0.20.1"
     api "org.springframework.security:spring-security-core:${springSecurityVersion}"
     api "org.springframework.security:spring-security-web:${springSecurityVersion}"
     api "org.springframework.security:spring-security-config:${springSecurityVersion}"