Add release notes for v2 runtime and opts

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

releases/v1.2.0-beta.0.toml

@@ -20,13 +20,37 @@ cases.
 ### New V2 Runtime
 
 A new v2 runtime has been added with a stable gRPC interface for managing
-containers through external plugins.
+containers through external shims.
+
+This allows runtime authors to easily integrate with containerd over a stable
+API.
+
+Various runtimes can be selected on a per container basis using the `WithRuntime` opt
+or to test via ctr `ctr run --runtime io.containerd.runc.v1`.
+
+[Documentation](https://github.com/containerd/containerd/blob/master/runtime/v2/README.md)
 
 ### New Proxy Plugins
 
 A new proxy plugin configuration has been added to allow external snapshotters
 be connected to containerd using gRPC.
 
+### Managed /opt directory
+
+A new `Install` method on the containerd client allows users to publish host level
+binaries using standard container build tooling and container distribution tooling
+to download containerd related binaries on their systems.
+
+This can be used for v2 runtime authors to get their runtime shims on an existing
+containerd system. It can also be used to install `runc` and other related tools.
+
+```bash
+> ctr content fetch docker.io/crosbymichael/runc:latest
+> ctr install docker.io/crosbymichael/runc:latest
+```
+
+[Documentation](https://github.com/containerd/containerd/blob/master/docs/managed-opt.md)
+
 ### API Changes
 
 Minor API additions