Fix docs url (#1689)

README.md

@@ -12,7 +12,7 @@
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 |[![Linux Build Status](https://dev.azure.com/caolanmcmahon/async/_apis/build/status/caolan.async?branchName=master&jobName=Linux&configuration=Linux%20node_10_x)](https://dev.azure.com/caolanmcmahon/async/_build/latest?definitionId=1&branchName=master) | [![Windows Build Status](https://dev.azure.com/caolanmcmahon/async/_apis/build/status/caolan.async?branchName=master&jobName=Windows&configuration=Windows%20node_10_x)](https://dev.azure.com/caolanmcmahon/async/_build/latest?definitionId=1&branchName=master) | [![MacOS Build Status](https://dev.azure.com/caolanmcmahon/async/_apis/build/status/caolan.async?branchName=master&jobName=OSX&configuration=OSX%20node_10_x)](https://dev.azure.com/caolanmcmahon/async/_build/latest?definitionId=1&branchName=master)| -->
 
-Async is a utility module which provides straight-forward, powerful functions for working with [asynchronous JavaScript](http://caolan.github.io/async/global.html). Although originally designed for use with [Node.js](https://nodejs.org/) and installable via `npm install async`, it can also be used directly in the browser.  A ESM version is included in the main `async` package that should automatically be used with compatible bundlers such as Webpack and Rollup.
+Async is a utility module which provides straight-forward, powerful functions for working with [asynchronous JavaScript](http://caolan.github.io/async/v3/global.html). Although originally designed for use with [Node.js](https://nodejs.org/) and installable via `npm install async`, it can also be used directly in the browser.  A ESM version is included in the main `async` package that should automatically be used with compatible bundlers such as Webpack and Rollup.
 
 A pure ESM version of Async is available as [`async-es`](https://www.npmjs.com/package/async-es).