use ruby 4.0 in CI

Author: rei-moo

.github/workflows/build.yml

@@ -10,12 +10,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: [ '2.6', '2.7', '3.0', '3.1', '3.2' ]
+        ruby: [ '2.6', '2.7', '3.0', '3.1', '3.2', '4.0' ]
 
     steps:
     - uses: actions/checkout@v4
     - name: Set up Ruby ${{ matrix.ruby }}
-      uses: ruby/setup-ruby@4a9ddd6f338a97768b8006bf671dfbad383215f4 #v1.190.0 tag
+      uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 #v1.268.0 tag
       with:
         ruby-version: ${{ matrix.ruby }}
         bundler-cache: true