Fix github token to use the default one on digest updater workflow (#853

)

Fix github token to use the default on digest updater workflow

.github/workflows/notebooks-digest-updater-upstream.yaml

@@ -89,7 +89,7 @@ jobs:
     needs: [ update-n-version ]
     runs-on: ubuntu-latest
     permissions:
-      contents: write
+      pull-requests: write
     steps:
       - name: Checkout repo
         uses: actions/checkout@v3
@@ -98,7 +98,7 @@ jobs:
         with:
           source_branch:  ${{ env.DIGEST_UPDATER_BRANCH }}
           destination_branch: ${{ env.BRANCH_NAME}}
-          github_token: ${{ secrets.GH_ACCESS_TOKEN }}
+          github_token: ${{ secrets.GITHUB_TOKEN }}
           pr_label: "automated pr"
           pr_title: "[Digest Updater Action] Update notebook's imageStreams image tag to digest format"
           pr_body: |