Update Known Issues in README

Author: Chuck Dumont

README.md

@@ -48,6 +48,7 @@
 - [Related plugins](#related-plugins)
 - [Sample application](#sample-application)
 - [Release Notes](#release-notes)
+- [Known Issues](#known-issues)
 - [Footnotes](#footnotes)
 
 <!-- TOC END -->
@@ -461,6 +462,10 @@ The versions of Dojo listed below require version 2.1.0 or later of this plugin
 
 In addition, Dojo loaders built with earlier versions of the plugin will not work with 2.1.0 or later, even if you have not changed the version of Dojo you are building with.  If you are using a pre-built loader with the [loader](#loader) config option, then you will need to rebuild it when upgrading to 2.1.
 
+# Known Issues
+
+There is a known issue with incrementally upgrading some versions of webpack to newer versions when using this plugin.  If, after upgrading webpack, you encounter the error "No hook for resolver normal in object ResolverFactory", try deletig your `node_modules` directory **and** your `package-lock.json` file and running `npm install` again to resolve the issue.
+
 # Footnotes
 
 <a name="foot1">1.</a>&nbsp; Embedded loader sizes are determined using a stand-alone embedded loader that has been uglified and gzipped.  The loader was produced as described in [Building the Dojo loader](#building-the-dojo-loader), with [the Dojo config API excluded](#the-dojo-config-api-feature) and using the 2.2.2 version of this plugin and the 1.14 Dojo loader, both of which support the new [`foreign-loader`](https://github.com/dojo/dojo/pull/279) has.js feature conditional.  Embedded loader sizes for earlier versions vary depending on the version of this plugin and of Dojo, up to a max of about 4KB when the Dojo config API is included.