Updating notes does not update all lines

首先，使用本报告中的内容对，通过 hackmd-cli notes create、hackmd-cli notes update 和 hackmd-cli export 命令复现该问题。比较更新一次和两次后的导出笔记，并确定 CLI 是否能够处理不一致的 HackMD API 响应；当最后一行能够可靠地更新时，即表示完成。

First of all, thanks for maintaining this tool.

Sometimes, when using the notes update command, the note is not fully updated. Here is a fairly small example/reproduction:

$ hackmd-cli notes create --content='
aa

```    
aab 
```

aab' 
 ID                     Title    User path Team path 
 ────────────────────── ──────── ───────── ───────── 
 59bbDYGPSESuaJuBh_fD4A Untitled gitmd         

to create a note with some content. Now, update it with some other content:

$ hackmd-cli notes update  --noteId 59bbDYGPSESuaJuBh_fD4A --content='
aa

```json
aabc
```

aabc'

However, the last modification (the last line) is not taken into account:

$ hackmd-cli export --noteId 59bbDYGPSESuaJuBh_fD4A

aa

```json
aabc
```

aab

If I do the hackmd-cli notes update command again, the content of the note matches what is required.
However, I've seen some old content/new content pairs where hackmd-cli notes update does nothing...

This seems to be a hackmd API bug (rather than the CLI), as I tried to directly write the HTTP requests, and it fails. But I could not find any github repository where we can file issues on the API itself. Feel free to redirect me if I'm not opening the issue in the right repo!

(while writing the HTTP requests by hand, I've also seen a case where writing a newline at the end of the JSON payload would change the outcome of the "update" API request... if that helps to track the bug)