fix 上传文件，后缀异常的bug

xueyi-modules/xueyi-file/src/main/java/com/xueyi/file/service/MinioSysFileServiceImpl.java

@@ -68,9 +68,12 @@ public class MinioSysFileServiceImpl implements ISysFileService {
 
     @Override
     public String uploadExactFile(MultipartFile file, String extension) throws Exception {
-        String fileName = FileUploadUtils.extractFilename(file);
-
-        fileName += extension;
+        String fileName = FileUploadUtils.extractFilename(file).replaceAll(extension, "");
+        if (fileName.charAt(fileName.length() - 1) == '.') {
+            fileName += extension;
+        } else {
+            fileName += "." + extension;
+        }
         //fileName = URLEncoder.encode(fileName, "UTF-8");
         log.info("Minio filename: {}" , fileName);
         PutObjectArgs args = PutObjectArgs.builder()