Replace/Remove links to private Google Docs in Changelog page

[mrshll1001]

Related issues

• Fixes #241

Description

The HSDS Changelog headers attempt to link off to further information surrounding the release of that version. However, versions 1.0 downwards linked off to private google docs.

HSDS has only been semi-consistent in creating releases on Github for versions. Some version headers link to issue queries filtered by milestones. This is acceptable where no release exists, however others link off to private, non-public, Google docs.

I have replaced the 1.0 link to the official GH release link, and removed the others for which there is no milestone, label, or release tag.

This means that for versions 0.x down, there are currently no header links. Links to the GDocs remain in the body of the changelog for that version. In the future, if these details are pulled through onto a public page or backported into Github; we can modify the headings with new links.

Merge checklist

• [ ] Update the changelog

If you have edited any schema files:

• [ ] Run hsds_schema.py to update datapackage.json and example files
• [ ] Update the logical model page if relevant

[greggish]

Thanks. The first couple of versions were managed in Google Docs. should we reclaim that content from the docs for historical purposes?