add write perms on pull requests (#250)

GitHub permissions are ANDed, not ORed. So, even though the sequester app was given permission to read and write pull requests, the configuration in YAML prevented it.

This ensures that if a PR is tagged as a work item, it will be imported correctly.

.github/workflows/quest-bulk.yml

@@ -14,6 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     permissions:
       issues: write
+      pull-requests: write
     if: ${{ github.repository_owner == 'dotnet' }}
     
     steps:

.github/workflows/quest.yml

@@ -21,6 +21,7 @@ jobs:
     runs-on: ubuntu-latest
     permissions:
       issues: write
+      pull-requests: write
 
     steps:
       - name: "Print manual run reason"