remove unused import

Author: ibalosh

src/main/java/com/postmarkapp/postmark/client/HttpClient.java

@@ -3,7 +3,6 @@
 import org.glassfish.jersey.client.ClientConfig;
 import org.glassfish.jersey.client.ClientProperties;
 import org.glassfish.jersey.client.HttpUrlConnectorProvider;
-import org.glassfish.jersey.grizzly.connector.GrizzlyConnectorProvider;
 
 import javax.ws.rs.client.Client;
 import javax.ws.rs.client.ClientBuilder;