dragonball: add dragonball into kata README
add dragonball description into kata README to help introduce dragonball
sandbox.
Fixes:
@@ -117,8 +117,8 @@ The table below lists the core parts of the project:
|-|-|-|
| [runtime](src/runtime) | core | Main component run by a container manager and providing a containerd shimv2 runtime implementation. |
| [agent](src/agent) | core | Management process running inside the virtual machine / POD that sets up the container environment. |
-| [libraries](src/libs) | core | Library crates shared by multiple Kata Container components or published to [`crates.io`](https://crates.io/index.ht
-ml) |
+| [libraries](src/libs) | core | Library crates shared by multiple Kata Container components or published to [`crates.io`](https://crates.io/index.html) |
+| [`dragonball`](src/dragonball) | core | An optional built-in VMM brings out-of-the-box Kata Containers experience with optimizations on container workloads |
| [documentation](docs) | documentation | Documentation common to all components (such as design and install documentation). |
| [libraries](src/libs) | core | Library crates shared by multiple Kata Container components or published to [`crates.io`](https://crates.io/index.html) |
| [tests](https://github.com/kata-containers/tests) | tests | Excludes unit tests which live with the main code. |
