Merge pull request #835 from cmu-delphi/ds/dependabot

bug(ci): use new secret for dependabot

Author: dshemetov

.github/workflows/dependabot-assignments.yml

@@ -7,7 +7,7 @@ jobs:
   dependabot:
     runs-on: ubuntu-latest
     env: 
-        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        GITHUB_PAT: ${{ secrets.CMU_DELPHI_AUTOMATION_MACHINE_DEPENDABOT_PAT }}
     if: ${{ github.actor == 'dependabot[bot]' }}
     steps:
       - name: Assign team to PR