Add homebrew to install

Author: avoidik

README.md

@@ -11,7 +11,13 @@ hands the session off to the AWS `session-manager-plugin`.
 
 ## Install
 
-Download a prebuilt binary for your platform (Linux/macOS, x86-64/arm64) from the
+Homebrew (macOS/Linux):
+
+```sh
+brew install avoidik/cshell/cshell
+```
+
+Or download a prebuilt binary for your platform (Linux/macOS, x86-64/arm64) from the
 [Releases](https://github.com/avoidik/cshell/releases) page, e.g.:
 
 ```sh