DEVDOCS-5718: [update] change back to node 18 (#27)

<!-- Ticket number or summary of work -->
# [DEVDOCS-5718]


## What changed?
See [Issue 17](#17) and [Issue 43](#43).

## Release notes draft
<!-- Provide an entry for the release notes using simple, conversational
language. Don't be too technical. Explain how the change will benefit
the merchant and link to the feature.

Examples:
* The newly-released [X feature] is now available to use. Now, you’ll be
able to [perform Y action].
* We're happy to announce [X feature], which can help you [perform Y
action].
* [X feature] helps you to create [Y response] using the [Z query
parameter]. Now, you can deliver [ex, localized shopping experiences for
your customers].
* Fixed a bug in the [X endpoint]. Now the [Y field] will appear when
you click [Z option]. -->
* 

## Anything else?
<!-- Add related PRs, salient notes, additional ticket numbers, etc. -->

ping {names}


[DEVDOCS-5718]:
https://bigcommercecloud.atlassian.net/browse/DEVDOCS-5718?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

docs/stencil-docs/installing-stencil-cli/installing-stencil.mdx

@@ -18,10 +18,6 @@ This article contains detailed instructions on installing and configuring Stenci
 To install Stencil CLI and its dependencies on Mac, open a terminal and run the following commands. Refer to [Stencil CLI README.MD](https://github.com/bigcommerce/stencil-cli) for latest `node` version supported.
 
 
-<Callout type="info">
- These instructions have been tested on **Mac OS X Yosemite**.
-</Callout>
-
 ```shell showLineNumbers copy
 # For ARM based macs
 arch -x86_64 /bin/zsh
@@ -30,10 +26,10 @@ arch -x86_64 /bin/zsh
 curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.0/install.sh | bash
 
 # Install Stencil CLI supported version of Node.js
-nvm install 20.10.0
+nvm install 18.15.0
 
 # Switch to Stencil CLI supported version of Node.js:
-nvm use 20.10.0
+nvm use 18.15.0
 
 # Install Stencil CLI
 npm install -g @bigcommerce/stencil-cli
@@ -56,7 +52,7 @@ choco install git
 
 # Install nvm windows and stencil-compatible node.js
 
-choco install nvm; nvm install 20.10.0; nvm use 20.10.0
+choco install nvm; nvm install 18.15.0; nvm use 18.15.0
 
 # Install Stencil CLI
 npm install -g @bigcommerce/stencil-cli
@@ -78,7 +74,7 @@ If you're a pro at installing and configuring Python and Node.js environments on
 
 **Required Dependencies:**
 * [Git](https://git-scm.com/downloads) - required to run npm install
-* [Node.js 20.10.0 and npm](https://nodejs.org/en/download/releases/) 
+* [Node.js 18.15.0 and npm](https://nodejs.org/en/download/releases/) 
 
 Once they're installed and configured, use `npm` to install Stencil CLI:
 
@@ -103,9 +99,9 @@ curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.36.0/install.sh | bash
 source ~/.bashrc
 
 # Explicitly install and use supported node version
-nvm install 20.10.0
+nvm install 18.15.0
 
-nvm use 20.10.0
+nvm use 18.15.0
 
 # Install stencil
 npm install -g @bigcommerce/stencil-cli