docs: update README with homebrew instructions for macos

- update `Content-Type` for build.sh

README.md

@@ -5,16 +5,26 @@ A CLI for generating [SSH Certificates](https://engineering.fb.com/2016/09/12/se
 SSH Certificates are easier to manage than SSH keys primarily because Certificates can expire automatically.
 This expiration means access to Sparkbox Slack is required to get SSH access to our various servers which strikes a good balance between security and maintenance overhead.
 
-## How to use
+## Installation
+
+### macOS
+
+1. `brew tap sparkbox/brew`
+1. `brew install sparkbox/brew/sb`
+
+### Linux
 
-1. Download `sb` from the [latest release](https://github.com/sparkbox/sb/releases) for your architecture.
-1. Unzip the file.
-1. *On a Mac, you will need to `control + click` the unzipped binary and select "Open" from the menu.*
+1. Download `sb` from the [latest release](https://github.com/sparkbox/sb/releases)
+1. Unzip the file
 1. Move the `sb` binary to a location your `$PATH` understands: e.g. `mv sb /usr/local/bin/sb`
 1. Start a fresh shell instance (new Terminal window)
+
+
+## How to use
+
 1. Login by running `sb login`. This should launch a Sign-in with Slack prompt in your browser. Paste the resultant ID and token back to `sb`.
-1. You're now set to generate a SSH Certificate, run `sb ssh`.
-1. Verify your local `ssh-agent` has the cert by running `ssh-add -l`and noting the `ECDSA-CERT` entry.
+1. Run `sb ssh` to generate a new, time limited SSH certificate.
+1. Run `ssh-add -l` to verify your local `ssh-agent` has the cert by locating the `ECDSA-CERT` entry.
 1. You can now SSH to any host that is configured to trust the Certificate Authority.
 
 ## How it works

build.sh

@@ -13,13 +13,15 @@ upload_file() {
     if [ "${NAME}" = "amd64-linux-sb" ]; then
         zip "${NAME}.zip" "${NAME}"
         NAME="${NAME}.zip"
+        CONTENT_TYPE="Content-Type: application/zip"
     else
         NAME="${NAME}.dmg"
+        CONTENT_TYPE="Content-Type: application/octet-stream"
     fi
 
     curl -H "Accept: application/vnd.github.v3+json" \
          -H "Authorization: Bearer ${GITHUB_TOKEN}" \
-         -H "Content-Type: application/zip" \
+         -H "${CONTENT_TYPE}" \
          --data-binary "@${NAME}" \
          "${UPLOAD_URL}?name=${NAME}"
 }