Previously published file share link is not updated when team renamed

### Is this a hackmd.io issue?

- [x] Yes, the bug happens on https://hackmd.io
- [ ] No. If it's a self-hosted CodiMD instance, please fire up the issue in the repo of CodiMD: https://github.com/hackmdio/codimd

### Read our Official tutorial

It's on https://hackmd.io/c/tutorials/

或是中文版 https://hackmd.io/c/tutorials-tw/

### What's the problem

A previously published file does not get updated when a team is renamed.

#### Current behaviour

> Screenshot (optional)

The actual URL should be `https://hackmd.io/@buildpacks/ByyEY9OZ8`

Provide steps to reproduce:

1. Create a note in a team work space and publish it publically.
2. Change team name
3. Go back to note
4. Click the share icon

Notice that the url still has the old team name.

#### Expected behaviour

I expected all notes created prior to renaming the team to have the new team name in the link so that they don't go to a 404. Maybe a redirect for the old URL would be nice but less expected.

#### Environment

I use HackMD on:

**Desktop**
- OS: macOS
- Browser: chrome
- Browser Version: 79.0.3945.130