v0.5.0

Breaking changes:

• The --import-key CLI option has been replaced with --import-keys. Otherwise, the same input is accepted for this option.

Other changes:

• Portier now has a logo! For now, this has only been added to our own landing page at portier.io, and as a favicon in the broker. Content of the broker pages has not changed. Thanks @feluxe for the design and @onli for the SVG work!
• It is now possible to export & import the private keys that were generated by the broker when using automatic key management. See docs/key-management.md for details.
• Cache headers for keys.json have been improved to use Expires instead of max-age, to better match client/proxy caching with our key rotation.
• Fixed parsing of trusted_proxies, which was ignored completely in previous versions.