chore: setup Gitpod (#422)

* simplify code contributions by fully automating the dev setup with Gitpod.

* docs: fix package name

Co-authored-by: Katashin <ktsn55@gmail.com>

Author: nisarhassan12

.gitpod.yml

@@ -0,0 +1,15 @@
+tasks:
+  - name: Compile
+    init: yarn install && yarn build && gp sync-done install
+    command: yarn dev
+  - name: Docs
+    init: gp sync-await install
+    command: yarn docs:dev
+
+ports:
+  - port: 8080
+    onOpen: open-preview
+
+vscode:
+  extensions:
+    - octref.vetur@0.23.0:TEzauMObB6f3i2JqlvrOpA== 

README.md

@@ -2,12 +2,18 @@
 
 ECMAScript / TypeScript decorator for class-style Vue components.
 
-[![npm](https://img.shields.io/npm/v/vue-class-component.svg)](https://www.npmjs.com/package/vue-class-component)
+[![npm](https://img.shields.io/npm/v/vue-class-component.svg)](https://www.npmjs.com/package/vue-class-component) [![Gitpod Ready-to-Code](https://img.shields.io/badge/Gitpod-Ready--to--Code-blue?logo=gitpod)](https://gitpod.io/#https://github.com/vuejs/vue-class-component) 
 
 ## Document
 
 See [https://class-component.vuejs.org](https://class-component.vuejs.org)
 
+## Online one-click setup for contributing
+
+Contribute to Vue Class Component using a fully featured online development environment that will automatically: clone the repo, install the dependencies and start the docs web server and run `yarn dev`.
+
+[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)
+
 ## Questions
 
 For questions and support please use the [the official forum](http://forum.vuejs.org) or [community chat](https://chat.vuejs.org/). The issue list of this repo is **exclusively** for bug reports and feature requests.