docs(readme): add Node.js version information (#4533)

* docs(readme): add Node.js version information

* docs(readme): spacing

README.md

@@ -43,6 +43,7 @@ visit our [code samples repo](https://github.com/aws-samples/aws-sdk-js-tests).
 1. [Install from Source](#install-from-source)
 1. [Giving feedback and contributing](#giving-feedback-and-contributing)
 1. [Release Cadence](#release-cadence)
+1. [Node.js versions](#nodejs-versions)
 1. [Stability of Modular Packages](#stability-of-modular-packages)
 1. [Known Issues](#known-issues)
    1. [Functionality requiring AWS Common Runtime (CRT)](#functionality-requiring-aws-common-runtime-crt)
@@ -514,6 +515,14 @@ For a full middleware stack deep dive please check out our [blog post](https://a
 Our releases usually happen once per weekday. Each release increments the
 minor version, e.g. 3.200.0 -> 3.201.0.
 
+## <a id="nodejs-versions"></a> Node.js versions
+
+v3.201.0 and higher requires Node.js >= 14.
+
+v3.46.0 to v3.200.0 requires Node.js >= 12.
+
+Earlier versions require Node.js >= 10.
+
 ## Stability of Modular Packages
 
 | Package name                | containing folder | API controlled by | stability     |