[llvm] ci: set minimal permission on github workflow (PR #69737)

[Diogo Teles Sant'Anna via llvm-commits]

https://github.com/diogoteles08 created https://github.com/llvm/llvm-project/pull/69737

Relates to #69736

>From d7aeaa56a7f8059bee38ece07da15972ec790989 Mon Sep 17 00:00:00 2001
From: Diogo Teles Sant'Anna <diogoteles at google.com>
Date: Fri, 20 Oct 2023 16:18:49 +0000
Subject: [PATCH] ci: set minimal permission on github workflow

Signed-off-by: Diogo Teles Sant'Anna <diogoteles at google.com>
---
 .github/workflows/libcxx-check-generated-files.yml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/.github/workflows/libcxx-check-generated-files.yml b/.github/workflows/libcxx-check-generated-files.yml
index 6f2d01ee0a56fdb..570055624b2a8d4 100644
--- a/.github/workflows/libcxx-check-generated-files.yml
+++ b/.github/workflows/libcxx-check-generated-files.yml
@@ -4,6 +4,9 @@ on:
     paths:
       - 'libcxx/**'
 
+permissions:
+  contents: read
+
 jobs:
   check_generated_files:
     runs-on: ubuntu-latest