Fix NPE when failed check update

Former-commit-id: da4873714b107eb409b86393763e1fdeb4950800 [formerly cd82b1280e14dafb384c35ff9bd79154006efafd]
Former-commit-id: 7e16e2d7b8147af70fe63ecdc4aaff90a71de78e

src/main/java/org/maxgamer/quickshop/Command/SubCommands/SubCommand_Update.java

@@ -9,6 +9,7 @@ import org.bukkit.scheduler.BukkitRunnable;
 import org.jetbrains.annotations.*;
 import org.maxgamer.quickshop.Command.CommandProcesser;
 import org.maxgamer.quickshop.QuickShop;
+import org.maxgamer.quickshop.Util.UpdateInfomation;
 import org.maxgamer.quickshop.Util.Updater;
 
 public class SubCommand_Update implements CommandProcesser {
@@ -20,7 +21,13 @@ public class SubCommand_Update implements CommandProcesser {
             @Override
             public void run() {
                 sender.sendMessage(ChatColor.YELLOW + "Checking for updates...");
-                if (Updater.checkUpdate().getVersion().equals(plugin.getDescription().getVersion())) {
+                UpdateInfomation updateInfomation = Updater.checkUpdate();
+                String updateVersion = updateInfomation.getVersion();
+                if (updateVersion == null) {
+                    sender.sendMessage(ChatColor.RED + "Failed check the update, connection issue?");
+                    return;
+                }
+                if (updateVersion.equals(plugin.getDescription().getVersion())) {
                     sender.sendMessage(ChatColor.GREEN + "No updates can update now.");
                     return;
                 }

src/main/java/org/maxgamer/quickshop/Util/UpdateInfomation.java

@@ -1,12 +1,13 @@
-package org.maxgamer.quickshop.Util;
-
-import lombok.*;
-
-@AllArgsConstructor
-@ToString
-@Getter
-@Setter
-public class UpdateInfomation {
-    private String version;
-    private boolean isBeta;
-}
+package org.maxgamer.quickshop.Util;
+
+import lombok.*;
+import org.jetbrains.annotations.*;
+
+@AllArgsConstructor
+@ToString
+@Getter
+@Setter
+public class UpdateInfomation {
+    @Nullable private String version;
+    private boolean isBeta;
+}