Use Ruby 4.0 for all workflows

Author: jbourassa

.github/workflows/build-docs.yml

@@ -26,7 +26,7 @@ jobs:
 
       - uses: oxidize-rb/actions/setup-ruby-and-rust@v1
         with:
-          ruby-version: "3.4"
+          ruby-version: "4.0"
           rustup-toolchain: "${{ env.NIGHTLY_VERSION }}"
           bundler-cache: true
           cargo-cache: true

.github/workflows/build-gems.yml

@@ -42,7 +42,7 @@ jobs:
 
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: "3.4"
+          ruby-version: "4.0"
 
       - uses: oxidize-rb/actions/cross-gem@v1
         id: cross-gem
@@ -66,7 +66,7 @@ jobs:
     strategy:
       matrix:
         os: ["ubuntu-latest"]
-        ruby: ["3.4"]
+        ruby: ["4.0"]
     steps:
       - uses: actions/checkout@v6
 

.github/workflows/memcheck.yml

@@ -7,10 +7,11 @@ on:
       ruby-version:
         description: "Ruby version to memcheck"
         required: true
-        default: "3.4"
+        default: "4.0"
         type: choice
         options:
           - "head"
+          - "4.0"
           - "3.4"
           - "3.3"
           - "3.2"
@@ -38,7 +39,7 @@ jobs:
 
       - uses: oxidize-rb/actions/setup-ruby-and-rust@v1
         with:
-          ruby-version: ${{ inputs.ruby-version || '3.4' }}
+          ruby-version: ${{ inputs.ruby-version || '4.0' }}
           bundler-cache: true
           cargo-cache: true
           cache-version: v2

.github/workflows/release.yml

@@ -42,7 +42,7 @@ jobs:
 
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: "3.4"
+          ruby-version: "4.0"
 
       - uses: oxidize-rb/actions/cross-gem@v1
         id: cross-gem
@@ -73,7 +73,7 @@ jobs:
 
       - uses: oxidize-rb/actions/setup-ruby-and-rust@v1
         with:
-          ruby-version: "3.4"
+          ruby-version: "4.0"
           bundler-cache: true
           cargo-cache: true
           cache-version: v1