fix(gha): exclude deleted workflows from zizmor scan (#13)

Author: kevya-google

.github/workflows/github_actions_scan.yml

@@ -39,7 +39,7 @@ jobs:
           GIT_HEAD_SHA: '${{ github.event.pull_request.head.sha }}'
           GIT_BASE_SHA: '${{ github.event.pull_request.base.sha }}'
         run: |
-          files=$(git diff --name-only "${GIT_BASE_SHA}" "${GIT_HEAD_SHA}" | grep -E '^\.github/workflows/.+\.ya?ml$' | xargs || true)
+          files=$(git diff --name-only --diff-filter=d "${GIT_BASE_SHA}" "${GIT_HEAD_SHA}" | grep -E '^\.github/workflows/.+\.ya?ml$' | xargs || true)
           echo "files=$files" >> "$GITHUB_OUTPUT"
 
   zizmor-scan: