Milestone is not assigned to merged PR

[krmanik]

Describe the bug
I am trying to add milestone to merged pull request but it seems it is not working.

To Reproduce
I have created and used this milestone.yml file to add milestone to merged PR.

name: PR Milestone

on:
  pull_request_target:
    types: [ closed ]

jobs:
  milestone:
    if: github.event.pull_request.merged == true && github.event.pull_request.milestone == null
    permissions:
      contents: read
      pull-requests: write    
    runs-on: ubuntu-latest
    steps:
    - uses: actions/github-script@v6
      with:
        script: |
          let result = await github.rest.issues.update({
            owner: context.repo.owner,
            repo: context.repo.repo,
            issue_number: ${{ github.event.pull_request.number }},
            milestone: 42
          });

          console.log(result);

Expected behavior
It should add milestone to the merged PR.

Additional context
I have used github scripts to remove labels and it works. But for milestone it does not.

[krmanik]

I am closing it because it needs to add issues: write in permissions also to make it works.