docs: add brew install instructions (#951)

website/content/docs/api-clients/desktop.mdx

@@ -26,7 +26,7 @@ $ boundary dev
 
 ### Install Boundary Desktop
 
-1. Download the latest .dmg installer from our [releases page](https://releases.hashicorp.com/boundary-desktop)
+1. Download the latest .dmg installer from our [releases page](https://releases.hashicorp.com/boundary-desktop). Alternatively, if you're a homebrew user, you can run `brew install hashicorp-boundary-desktop`
 1. Double-click the downloaded .dmg to run the installer
 1. Drag and drop Boundary into the applications folder
    ![](/img/boundary-desktop-drag-to-install.png)

website/content/docs/getting-started/index.mdx

@@ -14,8 +14,10 @@ Before getting started with Boundary, it's important to understand a few key con
 The examples in Getting Started all revolve around running in `dev mode`. There are a few requirements for running dev mode:
 
 1. [Docker](https://docs.docker.com/get-docker/) is installed
-2. A route to download the [Postgres Docker image](https://hub.docker.com/_/postgres) is available or a local image cache is available
-3. A [Boundary binary](https://www.boundaryproject.io/downloads) in your `$PATH`
+1. A route to download the [Postgres Docker image](https://hub.docker.com/_/postgres) is available or a local image cache is available
+1. A [Boundary binary](https://www.boundaryproject.io/downloads) in your `$PATH`
+1. Optionally, an [installation of Boundary Desktop](/docs/api-clients/desktop#install-boundary-desktop) if you want to use the
+desktop examples 
 
 ## What is Dev Mode?