[workflows] Add top-level permissions for libcxx-build-and-test.yaml

[tstellar]

This is the standard convention for our workflow files.

[llvmbot]

@llvm/pr-subscribers-github-workflow

Author: Tom Stellard (tstellar)

Changes

This is the standard convention for our workflow files.

---

Full diff: https://github.com/llvm/llvm-project/pull/73689.diff

1 Files Affected:

• (modified) .github/workflows/libcxx-build-and-test.yaml (+3)

diff --git a/.github/workflows/libcxx-build-and-test.yaml b/.github/workflows/libcxx-build-and-test.yaml
index dccfe54d4646767..e929c02d11c1d93 100644
--- a/.github/workflows/libcxx-build-and-test.yaml
+++ b/.github/workflows/libcxx-build-and-test.yaml
@@ -23,6 +23,9 @@ on:
       - 'cmake/**'
       - '.github/workflows/libcxx-build-and-test.yaml'
 
+permissions:
+  contents: read # Default everything to read-only
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
   cancel-in-progress: true