Set permissions for GitHub actions

- Included permissions for the action. https://github.com/ossf/scorecard/blob/main/docs/checks.md#token-permissions

https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#permissions

https://docs.github.com/en/actions/using-jobs/assigning-permissions-to-jobs

[Keeping your GitHub Actions and workflows secure Part 1: Preventing pwn requests](https://securitylab.github.com/research/github-actions-preventing-pwn-requests/)

 Restrict the GitHub token permissions only to the required ones; this way, even if the attackers will succeed in compromising your workflow, they won’t be able to do much.

Signed-off-by: naveensrinivasan <172697+naveensrinivasan@users.noreply.github.com>

.github/workflows/build.yml

@@ -5,6 +5,9 @@ name: Node.js CI
 
 on: [pull_request]
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ${{ matrix.os }}

.github/workflows/check_clang_format.yml

@@ -4,6 +4,9 @@ name: Check clang format
 # submitted branch.
 on: [pull_request]
 
+permissions:
+  contents: read
+
 jobs:
   clang-formatter:
     runs-on: ubuntu-latest

.github/workflows/update_metadata.yml

@@ -5,8 +5,14 @@ name: Update Metadata
 
 on: [workflow_dispatch]
 
+permissions:
+  contents: read
+
 jobs:
   update-metadata:
+    permissions:
+      contents: write  # for peter-evans/create-pull-request to create branch
+      pull-requests: write  # for peter-evans/create-pull-request to create a PR
     runs-on: ubuntu-latest        
 
     steps: