Update stable API URL of Vietnam

[trilwu]

No description provided.

[RichardMN]

I know why this is failing and think I can fix it (and test that the data download works) later this morning. Essentially we need to rebuild the available datasets file in data-raw

[RichardMN]

@ilumitr - I wasn't able to make the patches into your branch but here is what you would need to do to get your branch to pass (I think) the tests:

• build the package
• load the package
• source data-raw/render_available_datasets.R
• build the package again

This should update the Vietnam documentation and (critically) update the pre-rendered list of available datasets. One of our tests is to check that the pre-rendered list of available datasets matches what the package could render itself, and so this table needs to be rebuilt and updated in the repo.

Alternately, there is now #428 which is built on top of your branch with these steps applied.