Add doc links for 0.11.0 beta release

We maintain a table of documentation links for all released
versions of Tekton. Now that we have released the beta we
should add a link to those docs as well.

This commit adds a line of doc links for the beta release.

README.md

@@ -37,6 +37,7 @@ a cluster with **Kubernetes version 1.15 or later***.
 | Version | Docs | Examples |
 | ------- | ---- | -------- |
 | [HEAD](DEVELOPMENT.md#install-pipeline) | [Docs @ HEAD](/docs/README.md) | [Examples @ HEAD](/examples) |
+| [v0.11.0](https://github.com/tektoncd/pipeline/releases/tag/v0.11.0) | [Docs @ v0.11.0](https://github.com/tektoncd/pipeline/tree/v0.11.0/docs#tekton-pipelines) | [Examples @ v0.11.0](https://github.com/tektoncd/pipeline/tree/v0.11.0/examples#examples) |
 | [v0.11.0-rc4](https://github.com/tektoncd/pipeline/releases/tag/v0.11.0-rc4) | [Docs @ v0.11.0-rc4](https://github.com/tektoncd/pipeline/tree/v0.11.0-rc4/docs#tekton-pipelines) | [Examples @ v0.11.0-rc4](https://github.com/tektoncd/pipeline/tree/v0.11.0-rc4/examples#examples) |
 | [v0.11.0-rc3](https://github.com/tektoncd/pipeline/releases/tag/v0.11.0-rc3) | [Docs @ v0.11.0-rc3](https://github.com/tektoncd/pipeline/tree/v0.11.0-rc3/docs#tekton-pipelines) | [Examples @ v0.11.0-rc3](https://github.com/tektoncd/pipeline/tree/v0.11.0-rc3/examples#examples) |
 | [v0.11.0-rc2](https://github.com/tektoncd/pipeline/releases/tag/v0.11.0-rc2) | [Docs @ v0.11.0-rc2](https://github.com/tektoncd/pipeline/tree/v0.11.0-rc2/docs#tekton-pipelines) | [Examples @ v0.11.0-rc2](https://github.com/tektoncd/pipeline/tree/v0.11.0-rc2/examples#examples) |