v20

What's Changed

• Run shfmt by @josegonzalez in #55
• Test this buildpack by deploying to a dokku server by @josegonzalez in #56
• Split out workflows so that review app cleanup is properly run by @josegonzalez in #57
• Use correct remote host by @josegonzalez in #58
• Ensure test runs against vendored app-nginx.conf.sigil and mime.types by @josegonzalez in #59

Full Changelog: v19...v20