Add Dev Containers config

.devcontainer/devcontainer.json

@@ -0,0 +1,27 @@
+{
+    "name": "Echo Action",
+    "image": "mcr.microsoft.com/devcontainers/javascript-node:1-20-bookworm",
+    "postCreateCommand": "npm install",
+    "features": {
+        "ghcr.io/devcontainers/features/github-cli:1": {},
+        "ghcr.io/devcontainers-contrib/features/prettier:1": {}
+    },
+    "customizations": {
+        "codespaces": {
+            "openFiles": ["README.md"]
+        },
+        "vscode": {
+            "extensions": [
+                "EditorConfig.EditorConfig",
+                "DavidAnson.vscode-markdownlint",
+                "redhat.vscode-yaml",
+                "dbaeumer.vscode-eslint",
+                "esbenp.prettier-vscode"
+            ],
+            "settings": {
+                "editor.defaultFormatter": "esbenp.prettier-vscode",
+                "redhat.telemetry.enabled": false
+            }
+        }
+    }
+}

README.md

@@ -2,6 +2,7 @@
 
 [![License](https://img.shields.io/badge/License-MIT-green)](./LICENSE)
 [![Release](https://img.shields.io/github/v/release/imesense/gha-echo-action?include_prereleases&label=Release)](https://github.com/imesense/gha-echo-action/releases/tag/v0.2)
+[![Open in Dev Containers](https://img.shields.io/static/v1?label=Dev%20Containers&message=Open&color=blue&logo=visualstudiocode)](https://vscode.dev/redirect?url=vscode://ms-vscode-remote.remote-containers/cloneInVolume?url=https://github.com/imesense/gha-echo-action)
 [![Run action](https://github.com/imesense/gha-echo-action/actions/workflows/run-action.yml/badge.svg)](https://github.com/imesense/gha-echo-action/actions/workflows/run-action.yml)
 
 Simple action for printing input to output