SamlWebFilter: Adapt to pac4j version 3.4

Pac4J and its dependencies are not available on Maven Central.
However, recent builds can be found on the Schibboleth Consortium
(see https://www.shibboleth.net/)

Change-Id: I2fcf629fe8a6cf6ea4ba9c9e9fb411532960f9a8

build.sbt

diff --git a/build.sbt b/build.sbt
index 5648170..bb25ffc 100644
--- a/build.sbt
+++ b/build.sbt
@@ -10,7 +10,9 @@
 
 libraryDependencies += ("com.google.gerrit" % "gerrit-plugin-api" % GerritVersion % "provided")
 
-libraryDependencies += "org.pac4j" % "pac4j-saml" % "2.0.0-RC1"
+libraryDependencies += "org.pac4j" % "pac4j-saml" % "3.4.0"
+
+resolvers += "Shibboleth" at "https://build.shibboleth.net/nexus/content/repositories/releases/"
 
 libraryDependencies ~= { _ map {
   case m => m

src/main/java/com/thesamet/gerrit/plugins/saml/SamlWebFilter.java

diff --git a/src/main/java/com/thesamet/gerrit/plugins/saml/SamlWebFilter.java b/src/main/java/com/thesamet/gerrit/plugins/saml/SamlWebFilter.java
index 1550703..cef774a 100644
--- a/src/main/java/com/thesamet/gerrit/plugins/saml/SamlWebFilter.java
+++ b/src/main/java/com/thesamet/gerrit/plugins/saml/SamlWebFilter.java
@@ -43,6 +43,7 @@
 import org.pac4j.saml.client.SAML2ClientConfiguration;
 import org.pac4j.saml.credentials.SAML2Credentials;
 import org.pac4j.saml.profile.SAML2Profile;
+import org.pac4j.saml.state.SAML2StateGenerator;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -179,7 +180,9 @@
                 .getRequest()
                 .getRequestURI()
                 .substring(context.getRequest().getContextPath().length()));
-    context.setSessionAttribute(SAML2Client.SAML_RELAY_STATE_ATTRIBUTE, redirectUri);
+    context
+        .getSessionStore()
+        .set(context, SAML2StateGenerator.SAML_RELAY_STATE_ATTRIBUTE, redirectUri);
     log.debug("Setting redirectUri: {}", redirectUri);
     saml2Client.redirect(context);
   }