v3.0.0

This release introduces a completely new Docker scratch image base that is much smaller than before (down to 150MB from around 270MB before). It is intended to almost exactly mirror the agent as it will run outside of Docker so that we have parity between the two.

Also included is Kubernetes annotation config support (see https://github.com/signalfx/signalfx-agent/tree/master/docs/kubernetes-setup.md).

If you are manually configuring a monitor, the old serviceEndpoints config option has been merged with the top level monitor config (e.g. just put host and port directly on the monitor config object. You can only specify one custom endpoint per monitor config instance, but you can use YAML anchors/references to reduce duplication if you have a lot of manually specified hosts.

All of the collectd plugins that were previously configured implicitly are now explicitly configured in the monitor config. Be sure to add them or else you will lose several host-level metrics.

The procFSPath config option has been removed in favor of specifying it in the monitors that need it. This further decouples the monitors from the agent core for easier maintainability.

Discovery rule variables have changed from camelCased to snake_case so that they are consistent with our dimension names. Any dimensions that are added to a discovered endpoint can now be used in discovery rules. For example, you can now match on kubernetes_pod_name. The old camelCased variables are retained for backwards compatibility, but it is better to convert now.