Update update_zig_nightly.yml

.github/workflows/update_zig_nightly.yml

@@ -29,8 +29,7 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
           git remote set-url origin https://x-access-token:${GITHUB_TOKEN}@github.com/${GITHUB_REPOSITORY}.git
-          git diff --ignore-all-space --ignore-blank-lines --quiet
-          if [[ $? -ne 0 ]]; then
+          if ! git diff --ignore-all-space --ignore-blank-lines --quiet; then
             git add Casks/[email protected]
             git commit -m "Workflow update_zig_nightly: Updated Zig Nightly Cask to version $(grep 'version ".*"' | cut -d '"' -f2)"
             git push