.github/workflows/ofborg-pending.yml: delete (#370427)

Ofborg is dead for a few days, so this workflow is useless.

https://discourse.nixos.org/t/infrastructure-announcement-the-future-of-ofborg-your-help-needed/56025

.github/workflows/ofborg-pending.yml

@@ -1,34 +0,0 @@
-name: "Set pending OfBorg status"
-on:
-  pull_request_target:
-
-# Sets the ofborg-eval status to "pending" to signal that we are waiting for
-# OfBorg even if it is running late. The status will be overwritten by OfBorg
-# once it starts evaluation.
-
-# WARNING:
-# When extending this action, be aware that $GITHUB_TOKEN allows (restricted) write access to
-# the GitHub repository. This means that it should not evaluate user input in a
-# way that allows code injection.
-
-permissions:
-  contents: read
-
-jobs:
-  action:
-    name: set-ofborg-pending
-    if: github.repository_owner == 'NixOS'
-    permissions:
-      statuses: write
-    runs-on: ubuntu-latest
-    steps:
-    - name: "Set pending OfBorg status"
-      env:
-        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-      run: |
-        curl \
-          -X POST \
-          -H "Accept: application/vnd.github.v3+json" \
-          -H "Authorization: Bearer $GITHUB_TOKEN" \
-          -d '{"context": "ofborg-eval", "state": "pending", "description": "Waiting for OfBorg..."}' \
-          "https://api.github.com/repos/NixOS/nixpkgs/commits/${{ github.event.pull_request.head.sha }}/statuses"