Use Object Spread Syntax (#7777)

* Use Object Spread Syntax

* Nits

codemods/babel-plugin-codemod-object-assign-to-object-spread/README.md

@@ -0,0 +1,57 @@
+# @babel/plugin-codemod-object-assign-to-object-spread
+
+Transforms old code that uses `Object.assign` with an Object Literal as
+the first param to use Object Spread syntax.
+
+## Examples
+
+```js
+const obj = Object.assign({
+  test1: 1,
+}, other, {
+  test2: 2,
+}, other2);
+```
+
+Is transformed to:
+
+```js
+const obj = {
+  test1: 1,
+  ...other,
+  test2: 2,
+  ...other2,
+};
+```
+
+## Installation
+
+```sh
+npm install --save-dev @babel/plugin-codemod-object-assign-to-object-spread
+```
+
+## Usage
+
+### Via `.babelrc` (Recommended)
+
+**.babelrc**
+
+```json
+{
+  "plugins": ["@babel/plugin-codemod-object-assign-to-object-spread"]
+}
+```
+
+### Via CLI
+
+```sh
+babel --plugins @babel/plugin-codemod-object-assign-to-object-spread script.js
+```
+
+### Via Node API
+
+```javascript
+require("@babel/core").transform("code", {
+  plugins: ["@babel/plugin-codemod-object-assign-to-object-spread"]
+});
+```