Fix macOS ARM64 CI failure and update README Homebrew install instructions

.github/workflows/validate-homebrew.yml

@@ -31,11 +31,12 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Set up Homebrew
-        uses: Homebrew/actions/setup-homebrew@master
+        uses: Homebrew/actions/setup-homebrew@main
 
       - name: Tap and install modernize
         run: |
           brew tap ${{ github.repository }} https://github.com/${{ github.repository }}
+          brew trust ${{ github.repository }}
           brew install modernize
 
       - name: Extract expected version from formula

README.md

@@ -32,6 +32,7 @@ Minimum requirements:
 **Option 1 — Homebrew:**
 ```bash
 brew tap microsoft/modernize https://github.com/microsoft/modernize-cli
+brew trust microsoft/modernize
 brew install modernize
 ```