Split brew test-bot into separate steps to identify failing phase

Closes #24.

Signed-off-by: Sebastian Messmer <2373925+smessmer@users.noreply.github.com>

Author: claude

.github/workflows/tests.yml

@@ -34,7 +34,17 @@ jobs:
         run: brew install --cask macfuse
         shell: bash
 
-      - run: brew test-bot
+      - run: brew test-bot --only-cleanup-before
+        shell: bash
+
+      - run: brew test-bot --only-setup
+        shell: bash
+
+      - run: brew test-bot --only-tap-syntax
+        shell: bash
+
+      - run: brew test-bot --only-formulae
+        if: github.event_name == 'pull_request'
         shell: bash
 
       - name: Upload bottles as artifact