dependabot, use checkoutv4 in ci, update devcontainer

.devcontainer/devcontainer.json

@@ -3,7 +3,7 @@
 {
 	"name": "Ruby",
 	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
-	"image": "mcr.microsoft.com/devcontainers/ruby:1-3.2-bullseye"
+	"image": "mcr.microsoft.com/devcontainers/ruby:1-3.3-bullseye"
 
 	// Features to add to the dev container. More info: https://containers.dev/features.
 	// "features": {},

.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/ci.yml

@@ -14,7 +14,7 @@ jobs:
     env:
       RAILS_ENV: test
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with: