Update to Ruby 4.0.1

Bump actions/checkout from 4 to 6

.github/workflows/ci.yml

@@ -10,12 +10,12 @@ jobs:
   rubocop:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: 4.0.0
       - name: Cache Ruby gems
-        uses: actions/cache@v3
+        uses: actions/cache@v5
         with:
           path: vendor/bundle
           key: ${{ runner.os }}-bundle-4.0.0-${{ hashFiles('Gemfile.lock') }}
@@ -34,12 +34,12 @@ jobs:
       matrix:
         ruby-version: ["3.2.9", "3.3.10", "3.4.8", "4.0.0"]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby-version }}
       - name: Cache Ruby gems
-        uses: actions/cache@v3
+        uses: actions/cache@v5
         with:
           path: vendor/bundle
           key: ${{ runner.os }}-bundle-${{ matrix.ruby-version }}-${{ hashFiles('Gemfile.lock') }}

.ruby-version

@@ -1 +1 @@
-4.0.0
+4.0.1