edge-21.8.2

edge-21.8.2

This edge release continues the policy work by adding a new controller, written
in Rust, to expose a discovery API for inbound server policies. Apart from
that, this release includes a number of changes from external contributors; the
linkerd-jaeger helm chart now supports passing arguments to the Jaeger
container through the chart's values file. A number of unused functions and
variables have been also removed to improve the quality of the codebase.
Finally, this release also comes with changes to the proxy's outbound behavior,
a new extensions page on the dashboard, and support for querying service
metrics using the authority label in linkerd viz stat.

• Introduced new linkerd-policy-controller; the new controller is written in
  Rust and implements discovery APIs for inbound server policies, the container
  has been added to the linkerd-destination pod
• Updated linkerd-jaeger helm chart to support passing arguments to the
  Jaeger container (thanks @bsord!)
• Added support for querying service metrics using the authority label in
  linkerd viz stat
• Improved code hygiene by removing unused constants and functions throughout
  the codebase (thanks @xichengliudui!)
• Added a new extensions page to the dashboard to list all known built-in and
  third party extensions that can be used with Linkerd
• Changed outbound behavior in the proxy to tear down server-side connections
  when the remote proxy returns responses that indicate proxy errors; the
  connection in this case will be reset to allow clients to connect to a new
  endpoint