remove useless step in changelog workflow (#960)

Author: Alberto Iannaccone

.github/workflows/compose-full-changelog.yaml

@@ -32,7 +32,6 @@ jobs:
       - name: Create full changelog
         id: full-changelog
         run: |
-          yarn add @octokit/rest
           mkdir "${{ github.workspace }}/${{ env.CHANGELOG_ARTIFACTS }}"
 
           # Get the changelog file name to build