Test on Ruby 4.0 and Rails edge

Author: yaroslav

.github/workflows/rspec.yml

@@ -26,10 +26,10 @@ jobs:
             gemfile: "gemfiles/rails72.gemfile"
           - ruby: "3.4"
             gemfile: "gemfiles/rails8.gemfile"
-          - ruby: "3.4"
+          - ruby: "4.0"
             gemfile: "gemfiles/railsmaster.gemfile"
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}