GH-880: [CI] Fix syntax error in dev_pr.yml (#881)

## What's Changed

We can't write `permissions` in a step.

Closes #880.

Author: kou

.github/workflows/dev_pr.yml

@@ -35,6 +35,7 @@ concurrency:
 
 permissions:
   contents: read
+  issues: write
   pull-requests: write
 
 jobs:
@@ -80,9 +81,5 @@ jobs:
         if: '! github.event.pull_request.draft'
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        permissions:
-          contents: read
-          issues: write
-          pull-requests: write
         run: |
           ./.github/workflows/dev_pr_milestone.sh "${GITHUB_REPOSITORY}" ${{ github.event.number }}