Authors

Every post and page records who wrote it in two front matter fields (named in [site] author_field and author_id_field):

author: "Octo Cat"     # the name, as last written
author_id: "octocat"   # the GitHub login: who wrote it

• author_id identifies the author. Profile names can change at any time; the login is what Alasin matches avatars, My drafts, My recent posts and the author filter on. It can be written by hand too.
• author is the name as last written. The lists and the editor show the author's current GitHub name for their author_id, and saving a post writes that name to author. Someone who no longer has access keeps the name their posts last had. A post without author_id (e.g. by someone without a GitHub account) is shown by its author text; choose Someone else in the editor's author picker to write a name only.
• Names are never kept: Alasin reads them from GitHub every time, so a changed name shows at once.

Existing posts: posts written before author_id need it added once (for example with a small script that maps each author name to a login), so Alasin knows whose they are. Until then they are matched by name.

Showing authors on the site (optional)

Hugo can show the current GitHub name for author_id too. A partial such as layouts/partials/author.html:

{{- $name := .Params.author -}}
{{- with .Params.author_id -}}
  {{- $opts := dict -}}
  {{- with os.Getenv "HUGO_GITHUB_TOKEN" }}{{ $opts = dict "headers" (dict "Authorization" (printf "Bearer %s" .)) }}{{ end -}}
  {{- with try (resources.GetRemote (printf "https://api.github.com/users/%s" .) $opts) -}}
    {{- with .Value }}{{ with . | transform.Unmarshal }}{{ $name = or .name .login $name }}{{ end }}{{ end -}}
  {{- end -}}
{{- end -}}
{{ $name }}

It never fails the build: if GitHub doesn't answer, it shows author. So that names aren't kept between builds, turn Hugo's download cache off in the site configuration:

[caches.getresource]
maxAge = 0

Without a token GitHub allows 60 requests an hour, so set HUGO_GITHUB_TOKEN in the build environment (any token; it needs no permissions). A changed name shows on the site after the next build.