chore(docs): comment warning about Rosetta (#5567)

as copilot may fail with it

Addresses: #5566 



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site/content/docs/getting-started/install.en.md

@@ -6,6 +6,10 @@ You can install AWS Copilot through [Homebrew](https://brew.sh/) or by downloadi
 brew install aws/tap/copilot-cli
 ```
 
+??? info "Are you using Rosetta on a Mac machine with Apple silicon?"
+    If your homebrew was installed with [Rosetta](https://developer.apple.com/documentation/apple-silicon/about-the-rosetta-translation-environment), then the `brew install` will install the amd64 build. 
+    If this is not what you want, please either reinstall homebrew without Rosetta, or use the manual installation option below.
+
 ## Manually
 Copy and paste the command into your terminal.