Add indexed column webhook_id to scheduled products table

This is required to be able to associate a scheduled product
with an entity from a webhook payload, e.g. a PR on GitHub.
That is in turn required to be able to find a possibly already
existing scheduled product when a webhook is called, e.g. to
implement cancellation and cleanup in certain cases.

Related ticket: https://progress.opensuse.org/issues/127949

dbicdh/PostgreSQL/deploy/100/001-auto-__VERSION.sql

@@ -0,0 +1,18 @@
+--
+-- Created by SQL::Translator::Producer::PostgreSQL
+-- Created on Fri May 12 14:53:48 2023
+--
+;
+--
+-- Table: dbix_class_deploymenthandler_versions
+--
+CREATE TABLE dbix_class_deploymenthandler_versions (
+  id serial NOT NULL,
+  version character varying(50) NOT NULL,
+  ddl text,
+  upgrade_sql text,
+  PRIMARY KEY (id),
+  CONSTRAINT dbix_class_deploymenthandler_versions_version UNIQUE (version)
+);
+
+;