Update to javax.servlet-api 4.0.1

Closes gh-233

gradle/dependency-management.gradle

@@ -27,7 +27,7 @@ dependencyManagement {
 	dependencies {
 		dependency "com.nimbusds:oauth2-oidc-sdk:8.23.1"
 		dependency "com.nimbusds:nimbus-jose-jwt:9.1.3"
-		dependency "javax.servlet:javax.servlet-api:4.+"
+		dependency "javax.servlet:javax.servlet-api:4.0.1"
 		dependency 'junit:junit:latest.release'
 		dependency 'org.assertj:assertj-core:latest.release'
 		dependency 'org.mockito:mockito-core:latest.release'