Fix: enableSmtpApiErrorHooks should be Boolean

Changed enableSmtpApiErrorHooks from type String to type Boolean as the documentation states: https://postmarkapp.com/developer/api/servers-api

Author: MarioAOneDocument

src/main/java/com/wildbit/java/postmark/client/data/model/server/Server.java

@@ -27,14 +27,14 @@ public class Server {
     private String inboundDomain;
     private String inboundHash;
     private String inboundSpamThreshold;
-    private String enableSmtpApiErrorHooks;
+    private Boolean enableSmtpApiErrorHooks;
     private String deliveryType;
 
     // SETTERS AND GETTERS
 
-    public String getEnableSmtpApiErrorHooks() { return enableSmtpApiErrorHooks; }
+    public Boolean getEnableSmtpApiErrorHooks() { return enableSmtpApiErrorHooks; }
 
-    public void setEnableSmtpApiErrorHooks(String enableSmtpApiErrorHooks) { this.enableSmtpApiErrorHooks = enableSmtpApiErrorHooks; }
+    public void setEnableSmtpApiErrorHooks(Boolean enableSmtpApiErrorHooks) { this.enableSmtpApiErrorHooks = enableSmtpApiErrorHooks; }
 
     public Integer getId() {
         return id;