Update docs with 0.27.0 info

This commit adds links to the 0.27.0 version of the docs.

This commit also updates kubernetes version requirements from 1.18 to
1.19.

This commit also updates an old reference to the "master" branch of
pipelines, replacing it with "main".

README.md

@@ -30,14 +30,15 @@ Tekton Pipelines are **Typed**:
 - Jump in with [the tutorial!](docs/tutorial.md)
 - Take a look at our [roadmap](roadmap.md)
 
-*Note that starting from the 0.24 release of Tekton, you need to have
-a cluster with **Kubernetes version 1.18 or later***.
+*Note that starting from the 0.27 release of Tekton, you need to have
+a cluster with **Kubernetes version 1.19 or later***.
 
 ### Read the docs
 
 | Version | Docs | Examples |
 | ------- | ---- | -------- |
 | [HEAD](DEVELOPMENT.md#install-pipeline) | [Docs @ HEAD](/docs/README.md) | [Examples @ HEAD](/examples) |
+| [v0.27.0](https://github.com/tektoncd/pipeline/releases/tag/v0.27.0) | [Docs @ v0.27.0](https://github.com/tektoncd/pipeline/tree/v0.27.0/docs#tekton-pipelines) | [Examples @ v0.27.0](https://github.com/tektoncd/pipeline/tree/v0.27.0/examples#examples) |
 | [v0.26.0](https://github.com/tektoncd/pipeline/releases/tag/v0.26.0) | [Docs @ v0.26.0](https://github.com/tektoncd/pipeline/tree/v0.26.0/docs#tekton-pipelines) | [Examples @ v0.26.0](https://github.com/tektoncd/pipeline/tree/v0.26.0/examples#examples) |
 | [v0.25.0](https://github.com/tektoncd/pipeline/releases/tag/v0.25.0) | [Docs @ v0.25.0](https://github.com/tektoncd/pipeline/tree/v0.25.0/docs#tekton-pipelines) | [Examples @ v0.25.0](https://github.com/tektoncd/pipeline/tree/v0.25.0/examples#examples) |
 | [v0.24.3](https://github.com/tektoncd/pipeline/releases/tag/v0.24.3) | [Docs @ v0.24.3](https://github.com/tektoncd/pipeline/tree/v0.24.3/docs#tekton-pipelines) | [Examples @ v0.24.3](https://github.com/tektoncd/pipeline/tree/v0.24.3/examples#examples) |

docs/install.md

@@ -22,7 +22,7 @@ This guide explains how to install Tekton Pipelines. It covers the following top
 
 ## Before you begin
 
-1. You must have a Kubernetes cluster running version 1.18 or later.
+1. You must have a Kubernetes cluster running version 1.19 or later.
 
    If you don't already have a cluster, you can create one for testing with `kind`.
    [Install `kind`](https://kind.sigs.k8s.io/docs/user/quick-start/#installation) and create a cluster by running [`kind create cluster`](https://kind.sigs.k8s.io/docs/user/quick-start/#creating-a-cluster). This

tekton/release-cheat-sheet.md

@@ -138,7 +138,7 @@ the pipelines repo, a terminal window and a text editor.
 
     1. Publish the GitHub release once all notes are correct and in order.
 
-1. Edit `README.md` on `master` branch, add entry to docs table with latest release links.
+1. Edit `README.md` on `main` branch, add entry to docs table with latest release links.
 
 1. Push & make PR for updated `README.md`