Remove now-redundant PaaS-related things

Our Pact Broker instance has now been fully migrated to Heroku, so we can remove the old wrapper script that was used to run it on PaaS.

Some notes:

- The documentation about versioning is no longer valid because our new instance no longer uses a custom version parser
- The documentation related to deployment has been moved into the README
- Dependabot's bundler-related config has been removed because we no longer use Ruby in this repo
- Similarly, I have removed CodeQL SAST scanning because this repo no longer contains any code

.github/dependabot.yml

@@ -1,9 +1,5 @@
 version: 2
 updates:
-  - package-ecosystem: bundler
-    directory: /
-    schedule:
-      interval: daily
   - package-ecosystem: docker
     directory: /
     schedule:

.github/workflows/ci.yml

@@ -5,19 +5,9 @@ on:
   push:
     branches:
       - main
-    paths-ignore:
-      - "Jenkinsfile"
-      - ".git**"
-    pull_request:
-
+  pull_request:
 
 jobs:
-  codeql-sast:
-    name: CodeQL SAST scan
-    uses: alphagov/govuk-infrastructure/.github/workflows/codeql-analysis.yml@main
-    permissions:
-      security-events: write
-
   dependency-review:
     name: Dependency Review scan
     uses: alphagov/govuk-infrastructure/.github/workflows/dependency-review.yml@main

README.md

@@ -1,58 +1,12 @@
 # GOV.UK Pact Broker
 
-This repo is a thin wrapper around the [Pact Broker Gem][pact-broker-gem] that
-allows Pact Broker to be run on unicorn server on the
-[GOV.UK PAAS][government-paas].
-
-As PaaS is being decommissioned later this year, we are currently migrating
-Pact Broker to Heroku, and so this repo also contains a `Dockerfile` and
-associated `heroku.yml` file to allow it to run there. After the migration is
-complete, the leftover pieces of the old wrapper (`config.ru`, `Gemfile`,
-`Procfile`, etc.) will be removed from this repo.
+This repo contains a minimal configuration to allow the
+[pactfoundation/pact-broker](https://hub.docker.com/r/pactfoundation/pact-broker)
+Docker image to run on Heroku.
 
 Pact Broker is used by projects such as [Publishing API][publishing-api],
 [GDS API Adapters][gds-api-adapters] and [Content Store][content-store] for
 contract testing.
-
-## Getting started (legacy version)
-
-### Install dependencies
-
-```
-$ bundle install
-```
-
-### Create a PostgreSQL database
-
-```
-$ psql postgres
-> create database pact_broker;
-> CREATE USER pact_broker WITH PASSWORD 'pact_broker';
-> GRANT ALL PRIVILEGES ON DATABASE pact_broker to pact_broker;
-```
-
-### Set up environment variables
-
-```
-$ export AUTH_USERNAME=username
-$ export AUTH_PASSWORD=password
-$ export DATABASE_URL=postgresql://pact_broker@localhost/pact_broker
-```
-
-### Run the app
-
-```
-$ bundle exec unicorn
-```
-
-## Further documentation
-
-- [Infrastructure](docs/infrastructure.md)
-- [Deployment](docs/deployment.md)
-- [Versioning](docs/versioning.md)
-
-[pact-broker-gem]: https://github.com/bethesque/pact_broker
-[government-paas]: https://docs.cloud.service.gov.uk/
 [publishing-api]: https://github.com/alphagov/publishing-api
 [gds-api-adapters]: https://github.com/alphagov/gds-api-adapters
 [content-store]: https://github.com/alphagov/content-store