Test against Ruby 4.0 (#23)

Author: tagliala

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['2.6', '2.7', '3.0', '3.1', '3.2', '3.3', '3.4']
+        ruby-version: ['2.6', '2.7', '3.0', '3.1', '3.2', '3.3', '3.4', '4.0']
         channel: ['stable']
 
         include:

.github/workflows/rubocop.yml

@@ -19,7 +19,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        ruby-version: ['3.4']
+        ruby-version: ['4.0']
 
     steps:
     - uses: actions/checkout@v4