Make api a Go sub-module

Allow the api to stay at the same v1 go package name and keep using a
1.x version number. This indicates the API is still at 1.x and allows
sharing proto types with containerd 1.6 and 1.7 releases.

Signed-off-by: Derek McGowan <derek@mcg.dev>

cmd/ctr/commands/events/events.go

@@ -27,7 +27,7 @@ import (
 	"github.com/urfave/cli/v2"
 
 	// Register grpc event types
-	_ "github.com/containerd/containerd/v2/api/events"
+	_ "github.com/containerd/containerd/api/events"
 )
 
 // Command is the cli command for displaying containerd events