ci.yml in jekyll-toc-0.17.0

- old
+ new
@@ -2,30 +2,22 @@
 on: [push, pull_request]
 jobs:
   build:
     strategy:
       matrix:
-        ruby: [2.4, 2.5, 2.6, 2.7]
+        ruby: [2.5, 2.6, 2.7, 3.0]
         gemfile:
-          - gemfiles/jekyll_3.8.gemfile
           - gemfiles/jekyll_3.9.gemfile
           - gemfiles/jekyll_4.0.gemfile
           - gemfiles/jekyll_4.1.gemfile
           - gemfiles/jekyll_4.2.gemfile
-        exclude:
-        - ruby: 2.4
-          gemfile: gemfiles/jekyll_4.0.gemfile
-        - ruby: 2.4
-          gemfile: gemfiles/jekyll_4.1.gemfile
-        - ruby: 2.4
-          gemfile: gemfiles/jekyll_4.2.gemfile
     env:
       BUNDLE_GEMFILE: ${{ matrix.gemfile }}
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
     - name: Set up Ruby ${{ matrix.ruby }}
-      uses: actions/setup-ruby@v1
+      uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
     - name: bundle install
       run: |
         gem install bundler