Chore: update from GetJSON to GetRemote

[SallyMcGrath]

GetJSON is deprecated in https://github.com/gohugoio/hugo/releases/tag/v0.123.0
We should use instead GetRemote

Here's an example in #773 :

https://github.com/CodeYourFuture/curriculum/pull/773/files?file-filters%5B%5D=.html&show-viewed-files=true

It's basically the same except

1. You now have to put headers inside a dict called "headers"
2. You now always have to unmarshal your response eg response.Content | transform.Unmarshal (basically like JSON.parse() )

On the upside, apparently soon we will have richer access to headers in response.Data

Places this touches

• issues.html (but I have done this one Feature: make issues and github stuff work outside of CYF #773 )
• readme.html
• pd.html
• pullreq.html
• parsed.html

[SallyMcGrath]

I did all these in #824 #820 #815