Use Bearer auth for GitHub API

[fhunleth]

This is a transparent change to users. Bearer auth doesn't need the
username, so it's ignored if users provide it.

[Copilot]

Pull request overview

Updates the GitHub API artifact resolver to use Bearer token authentication instead of Basic auth, and refreshes tests/docs accordingly so users only need to provide a token (and tag) for private GitHub releases.

Changes:

• Switch Nerves.Artifact.Resolvers.GithubAPI Authorization header from Basic ... to Bearer ....
• Update resolver tests to assert Bearer auth behavior.
• Update documentation and guides to remove username from :github_api examples.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
lib/nerves/artifact/resolvers/github_api.ex	Changes Authorization header construction to Bearer auth and removes :username from the struct.
test/nerves/artifact/resolvers_github_api_test.exs	Updates mocked header assertions from Basic to Bearer.
lib/nerves/artifact.ex	Updates :github_api example usage in docs.
guides/advanced/systems.md	Updates :github_api examples and wording to remove username.
guides/advanced/customizing-systems.md	Updates the list of supported artifact site helpers to remove username for :github_api.

Comments suppressed due to low confidence (1)

lib/nerves/artifact/resolvers/github_api.ex:32

• get/2 builds the options struct via struct(__MODULE__, opts), which raises KeyError on any unknown keys. Since this PR removes :username from the struct, existing callers that still pass username: ... (per previous docs) will now crash instead of being "ignored". To keep this change transparent, either keep :username in the struct (even if unused) or drop that key from opts before calling struct/2.

  def get({org_proj, opts}, dest_path) do
    opts =
      %{struct(__MODULE__, opts) | opts: opts, repo: org_proj}
      |> maybe_adjust_token()
      |> add_http_opts()

---

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

lib/nerves/artifact/resolvers/github_api.ex:31

• Removing :username from the resolver struct is a breaking change for existing configs. get/2 calls struct(__MODULE__, opts), which raises if opts contains unknown keys (e.g. username:). If the intent is to transparently ignore usernames, either keep username in the struct for backward compatibility or drop :username (and any other deprecated keys) from opts before calling struct/2 (e.g. in get/2 or in Artifact.expand_site/3).

  defstruct artifact_name: nil,
            base_url: @base_url,
            headers: [],
            public?: false,
            opts: [],
            repo: nil,
            tag: "",
            token: "",
            url: nil

  @impl Nerves.Artifact.Resolver
  def get({org_proj, opts}, dest_path) do
    opts =
      %{struct(__MODULE__, opts) | opts: opts, repo: org_proj}
      |> maybe_adjust_token()

---

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