add ci for ruby 3.1, 3.2, 3.3, head. Drop 2.7 and below

.devcontainer/devcontainer.json

@@ -0,0 +1,19 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/debian
+{
+	"name": "Debian",
+	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+	"image": "mcr.microsoft.com/devcontainers/base:bullseye"
+
+	// Features to add to the dev container. More info: https://containers.dev/features.
+	// "features": {},
+
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	// "forwardPorts": [],
+
+	// Configure tool-specific properties.
+	// "customizations": {},
+
+	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+	// "remoteUser": "root"
+}

.github/dependabot.yml

@@ -0,0 +1,12 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for more information:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+# https://containers.dev/guide/dependabot
+
+version: 2
+updates:
+ - package-ecosystem: "devcontainers"
+   directory: "/"
+   schedule:
+     interval: weekly

.github/workflows/test.yml

@@ -9,16 +9,15 @@ jobs:
     strategy:
       matrix:
         ruby-version:
-          - 2.3
-          - 2.4
-          - 2.5
-          - 2.6
-          - 2.7
           - '3.0'
+          - '3.1'
+          - '3.2'
+          - '3.3'
+          - 'head'
           - jruby-9.2.19.0
           - jruby-9.3.0.0
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Set up Ruby ${{ matrix.ruby-version }}
       uses: ruby/setup-ruby@v1
       with: