fix(release): remove checkout and pull steps to keep workflow referen… (

#6737)

running into errors in generate changelog action where it can't create
the PRs due to conflicts, this removes the non essential git
configuration steps to keep the reference branch the same


## Test plan
N/A, couldn't test locally need the github UI
<!-- Required. See
https://docs-legacy.sourcegraph.com/dev/background-information/testing_principles.
-->

.github/workflows/generate-changelog.yml

@@ -20,8 +20,6 @@ jobs:
           git config --global user.name 'sourcegraph-bot'
           git config --global user.email 'bot@sourcegraph.com'
           git fetch --tags origin
-          git checkout main
-          git pull
       - name: Download changelog
         env:
           GH_TOKEN: ${{ secrets.DEVX_SERVICE_GH_TOKEN }}