[skip ci] Limit "Update clang" step to 10 minutes

Just like brew this can stall, apparently...

Author: iluuu1994

.github/workflows/nightly.yml

@@ -310,6 +310,7 @@ jobs:
         with:
           ref: ${{ fromJson(inputs.branch).ref }}
       - name: Update clang
+        timeout-minutes: 10
         uses: ./.github/actions/macos-update-clang
       - name: brew
         timeout-minutes: 10