DEPR: deprecate cols / change to columns in to_csv / to_excel

[jreback]

related is #6581

[jreback]

cc @jsexauer

[jsexauer]

I'm trying to convert this issue into a PR using the API:

URI: https://api.github.com/repos/pydata/pandas/pulls
POST Payload: {"head": "jsexauer:fix6645", "base": "master", "issue":"6645"}
Response:

{
  "message": "Validation Failed",
  "documentation_url": "http://developer.github.com/v3/pulls/#create-a-pull-request",
  "errors": [
    {
      "resource": "PullRequest",
      "field": "issue",
      "code": "unauthorized"
    }
  ]
}

I've done this before successfully but now it says I'm unauthorized. Any idea why this may be?

[jreback]

never tried using the API
I just go to the branch an pull it on the website

[jsexauer]

But won't that create a new issue number?

[jreback]

yep
you want to do that
the pr will then close this issue