Switch to danger-pr-comment for PR checks

Replace ruby-grape-danger with danger-pr-comment to align with
the grape repo's two-workflow approach: one workflow runs Danger,
another posts the results as PR comments.

Author: numbata

.github/workflows/danger-comment.yml

@@ -0,0 +1,11 @@
+name: Danger Comment
+
+on:
+  workflow_run:
+    workflows: [Danger]
+    types: [completed]
+
+jobs:
+  comment:
+    uses: numbata/danger-pr-comment/.github/workflows/danger-comment.yml@v0.1.0
+    secrets: inherit

.github/workflows/danger.yml

@@ -0,0 +1,13 @@
+name: Danger
+
+on:
+  pull_request:
+    types: [opened, reopened, edited, synchronize]
+
+jobs:
+  danger:
+    uses: numbata/danger-pr-comment/.github/workflows/danger-run.yml@v0.1.0
+    secrets: inherit
+    with:
+      ruby-version: '3.4'
+      bundler-cache: true

Dangerfile

@@ -1,3 +1,5 @@
 # frozen_string_literal: true
 
-danger.import_dangerfile(gem: 'ruby-grape-danger')
+danger.import_dangerfile(gem: 'danger-pr-comment')
+
+changelog.check!

Gemfile

@@ -23,6 +23,8 @@ group :test do
   gem 'guard-bundler'
   gem 'guard-rspec'
   gem 'rb-fsevent'
-  gem 'ruby-grape-danger', '~> 0.2', require: false
+  gem 'danger', require: false
+  gem 'danger-changelog', require: false
+  gem 'danger-pr-comment', require: false
   gem 'simplecov', require: false
 end