.mergify.yml: drop (#423506)

queue_rules:

  # This rule is for https://docs.mergify.com/commands/queue/

  # and can be triggered with: @mergifyio queue

  - name: default

    merge_conditions:

      # all github action checks in this list are required to merge a pull request

      - check-success=Attributes

      - check-success=Check

      - check-success=Outpaths (aarch64-darwin)

      - check-success=Outpaths (aarch64-linux)

      - check-success=Outpaths (x86_64-darwin)

      - check-success=Outpaths (x86_64-linux)

      - check-success=Process

      - check-success=Request

      - check-success=editorconfig-check

      - check-success=label-pr

      - check-success=nix-files-parseable-check

      - check-success=nixfmt-check

      - check-success=nixpkgs-vet

    # queue up to 5 pull requests at a time

    batch_size: 5