发送进度报告兼容BUG经办人为空的情况

src/main/java/cn/qg/holmes/utils/DingdingUtils.java

@@ -127,7 +127,13 @@ public class DingdingUtils {
             content = content + count + "、[" + issue.getSummary().replace("\"", "") + "](" + issueUrl + ")\n";
             content = content + "- 优先级：" + issue.getPriority().getName() + "\n";
             content = content + "- 状态：" + issue.getStatus().getName() + "\n";
-            content = content + "- 经办人：" + issue.getAssignee().getDisplayName() + "\n\n";
+            String assignee = "";
+            if (issue.getAssignee() == null) {
+                assignee = "未分配";
+            } else {
+                assignee = issue.getAssignee().getDisplayName();
+            }
+            content = content + "- 经办人：" + assignee + "\n\n";
         }
         if (risk != null && !risk.isEmpty()) {
             content += "**风险：**\n\n";