Update default Ruby version to 4.0.0

- Update .ruby-version files in both example apps to 4.0.0
- Add Ruby 4.0 to CI matrix and set it for coverage reporting
- CI now tests against Ruby 4.0, 3.4, 3.3, and 3.2

Author: mensfeld

.github/workflows/ci.yml

@@ -36,11 +36,12 @@ jobs:
       fail-fast: false
       matrix:
         ruby:
+          - '4.0'
           - '3.4'
           - '3.3'
           - '3.2'
         include:
-          - ruby: '3.4'
+          - ruby: '4.0'
             coverage: 'true'
     steps:
       - uses: actions/checkout@v5
@@ -95,11 +96,12 @@ jobs:
       fail-fast: false
       matrix:
         ruby:
+          - '4.0'
           - '3.4'
           - '3.3'
           - '3.2'
         include:
-          - ruby: '3.4'
+          - ruby: '4.0'
             coverage: 'true'
     steps:
       - uses: actions/checkout@v5

v2.5-non-rails/.ruby-version

@@ -1 +1 @@
-3.4.5
+4.0.0

v2.5-rails/.ruby-version

@@ -1 +1 @@
-3.4.5
+4.0.0