fix: 创建gitlab用户id不匹配

seecoder-gitlab-client/src/main/java/com.nju.edu.gitlab/SeecoderGitlabClient.java

@@ -94,7 +94,7 @@ public class SeecoderGitlabClient implements SeecoderGitlabApi{
                                                     .username(username)
                                                     .build();
             builder = builder
-                    .url(host + "/api/user")
+                    .url(host + "/api/user/")
                     .post(RequestBody.create(MediaType.parse("application/json; charset=utf-8"), objectMapper.writeValueAsString(gitlabUserDTO)));
             Request request = builder.build();
             final Call call = client.newCall(request);