Incorrect bot action in invenia/FTPClient.jl

@ararslan has indicated an incorrect bot action in https://github.com/invenia/FTPClient.jl/pull/84
The relevant snippets are shown below:

```diff
@@ -145,7 +145,7 @@ end
     ftp = FTP(; opts...)
     local_file = upload_file
     server_dir = joinpath(HOMEDIR, testdir)
-    mkdir(ftp, testdir)
+    mkdir(ftp, mode=testdir)
```