docs: Add readme screenshot

Author: mskelton

README.md

@@ -4,7 +4,9 @@
 [![All Contributors](https://img.shields.io/github/all-contributors/mskelton/vscode-npm-outdated?color=orange)](#contributors-)
 [![Semantic release](https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg)](https://github.com/semantic-release/semantic-release)
 
-> Displays a warning in package.json files for packages which have newer versions available.
+Displays a diagnostic message in package.json files for packages which have newer versions available as well as a code action to quickly update packages to their latest version.
+
+![Screenshot](./assets/screenshot.jpg)
 
 ## Contributors ✨
 

icon.png assets/icon.pngicon.png renamed to assets/icon.png

@@ -1,7 +1,7 @@
 {
   "name": "npm-outdated",
   "displayName": "npm Outdated",
-  "description": "Displays a warning in package.json files for packages which have newer versions available.",
+  "description": "Displays a diagnostic message in package.json files for packages which have newer versions available.",
   "version": "0.0.0-semantically-released",
   "publisher": "mskelton",
   "author": "Mark Skelton",
@@ -32,7 +32,7 @@
     "start": "webpack --watch",
     "vscode:prepublish": "npm run build"
   },
-  "icon": "icon.png",
+  "icon": "./assets/icon.png",
   "engines": {
     "vscode": "^1.49.0"
   },