chore: update Standardrb, configure Rubocop to use Standard rules

[Envek]

As Standardrb is based on Rubocop and default Rubocop configuration is dramatically different from Standardrb opinions, my editor detected .rubocop.yml and became mad and tried to autocorrect everything to Rubocop default style.

So I decided to make Rubocop to obey Standardrb rules so they are in sync (see Running Standard's rules via RuboCop)

Updated gems and github actions along the way

[dduugg]

PR Review: "chore: update Standardrb, configure Rubocop to use Standard rules"

Goal

Two things: (1) configure RuboCop to inherit Standard's rules so that editor RuboCop integrations stop fighting with Standard, and (2) update Standard and related gems to their latest versions. The GitHub Actions workflow is also modernized along the way.

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What's Already on main

PR #59 (just merged) already added permissions: checks: write / contents: read to standardrb.yaml, so there will be a minor merge conflict there. Everything else in this PR is new.

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Implementation

• .rubocop.yml: Adds require and inherit_gem directives so RuboCop loads Standard's rule set directly. This makes editor RuboCop plugins agree with standardrb on style.
• .standard.yml: Removes extend_config: - .rubocop.yml — that directive was pointing Standard at RuboCop config, but the relationship is now inverted (RuboCop inherits from Standard). Keeping it would cause a circular reference.
• .github/workflows/standardrb.yaml:
  • Renames job build → standardrb (clearer name).
  • Removes the separate actions/checkout@v1 step — standard-ruby-action@v1 handles checkout itself.
  • Upgrades action from v0.0.5 → v1.
  • Adds permissions: checks: write / contents: write.
• Gemfile.lock: Bumps standard 1.35.1 → 1.54.0, rubocop 1.62.1 → 1.84.2, and transitive deps.
• lib/singed.rb / lib/singed/cli.rb: Removes two unused require "pathname" lines (likely surfaced by the updated linter).

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Risk Assessment

Low risk overall. This is tooling/config only — no production code changes beyond removing two unused require lines.

1. contents: write is broader than necessary

PR #59 landed with contents: read. This PR uses contents: write. The StandardRB action only needs to read code and post check results — contents: write grants it push access to the repo, which is more than required. Recommend keeping contents: read from #59.

2. Minor merge conflict with PR #59

The standardrb.yaml diff will conflict with what #59 already merged (permissions block, job still named build). The resolution is straightforward: keep contents: read from #59 and apply the remaining changes (rename job, upgrade action version, remove checkout step) from this PR.

3. TargetRubyVersion: 2.7 in .rubocop.yml may be outdated

The existing .rubocop.yml targets Ruby 2.7. The CI matrix (from build.yml) tests against 3.2, 3.3, 3.4, and 4. Worth bumping TargetRubyVersion to at least 3.2 to get accurate cop behavior — though this is a pre-existing issue, not introduced by this PR.

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Summary

Good housekeeping PR. The .rubocop.yml + .standard.yml change is the main substance and is correct. Main items before merging:

• Resolve the minor merge conflict with #59 in standardrb.yaml; keep contents: read rather than contents: write
• Optionally bump TargetRubyVersion to match the minimum supported Ruby (pre-existing issue, but good to fix while touching the file)

[Envek]

1. contents: write is broader than necessary

That allow standardrb action to automatically fix pushed code in a follow-up commit. See autofix option (enabled by default): https://github.com/standardrb/standard-ruby-action#:~:text=autofix

If it is not desired we can rollback this change.

2. Minor merge conflict with PR Fix StandardRB check failing on Dependabot PRs #59

Resolved

3. TargetRubyVersion: 2.7 in .rubocop.yml may be outdated

It was in sync with gemspec before #55, updated to 3.2 accordingly

[dduugg]

Thanks @Envek! The permission is intentional — we want the autofix behavior. All three review points are addressed. Merging.