Pomerium v0.4.0 is released

[Bobby DeSimone]

I'm happy to announce Pomerium 0.4.0 is now released! This release includes some great new features, including:

• Forward-auth integration with third-party ingresses and proxies.
  
• Insecure transport support for SSL termination configurations.
• Many other fixes and improvements.

Please review the upgrade guide and changelog for a complete list of changes.

As always, you can download binary and source distributions from github or by pulling the `latest`/`v0.4.0` container images from dockerhub.

Thank you to everyone who contributed to the release. 

Bobby