Add required files for renovate bot workflow

As outlined in: https://github.com/renovatebot/github-action

.github/renovate-entrypoint.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+set -e
+
+echo "=== Starting Renovate Bot ==="
+
+apt update
+apt install -y build-essential libpq-dev
+
+runuser -u ubuntu renovate --platform=github
+
+echo "=== Renovate Bot finished ==="