- Update to version 2.3.0:
* news: add notes for 2.3.0
* config/v3_2_experimental: update all copyright dates
* doc/configuration-*: update for new spec
* tests: stabilize spec 3.1.0
* *: update for new experimental spec
* config/v3_2_experimental: set up package
* config/v3_2_experimental: copy from config/v3_1
* config/v3_1_experimental: mark stable
* doc/development: update spec stabilization instructions
* config: rename function for clarity
* tests: bump invalid 2.x experimental version to match spec2x branch
* config/v3_1_experimental: add some missing version tests
* config/v3_1/translate: fix package name
* doc/migrating-configs: update for 3.1.0
* resource/url: allow compression in data URLs
* doc/migrating-configs: mention spec 2.4.0
* validate: accept any supported config version
* exec: drop validate.go
* doc/migrating-configs: put newest version first
* Add SHA-256 reference in the docs
* Add SHA-256 support for file verification
* ci: run blackbox tests in CoreOS CI
* Send ssh_authorized keys info into the journald log
* Update go-systemd with the systemd module
* Send a message to the systemd journal if a user config is provided
* tests: add positive tests for resource compression
* spec: unify resource fetching type
* doc: clarify wording of files.*.verification.hash
* vendor: refresh after gomod changes
* gomod: update to go-systemd v22
* stages: fix package names
* providers/packet: override Accept header fetching instance metadata
* resource/url: allow caller-specified headers to override defaults
* Allow to specify HTTP headers for fetching configs and files