[Docs]: Updated README.md to include homebrew unsecure dirs warning

Closes #2361.

README.md

@@ -51,7 +51,7 @@
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 
 ## About
-nvm is a version manager for [node.js](https://nodejs.org/en/), designed to be installed per-user, and invoked per-shell. `nvm` works on any POSIX-compliant shell (sh, dash, ksh, zsh, bash), in particular on these platforms:  unix, macOS, and windows WSL.
+nvm is a version manager for [node.js](https://nodejs.org/en/), designed to be installed per-user, and invoked per-shell. `nvm` works on any POSIX-compliant shell (sh, dash, ksh, zsh, bash), in particular on these platforms: unix, macOS, and windows WSL.
 
 <a id="installation-and-update"></a>
 <a id="install-script"></a>
@@ -862,3 +862,12 @@ To change the user directory and/or account name follow the instructions [here](
 [4]: https://github.com/nvm-sh/nvm/releases/tag/v0.37.2
 [Urchin]: https://github.com/scraperwiki/urchin
 [Fish]: http://fishshell.com
+
+**Homebrew makes zsh directories unsecure**
+
+```shell
+zsh compinit: insecure directories, run compaudit for list.
+Ignore insecure directories and continue [y] or abort compinit [n]? y
+```
+
+Homebrew causes insecure directories like `/usr/local/share/zsh/site-functions` and `/usr/local/share/zsh`. This is **not** an `nvm` problem - it is a homebrew problem. Refer [here](https://github.com/zsh-users/zsh-completions/issues/680) for some solutions related to the issue.