[Doc] Try new features before release (Azure#11784)

* [Doc] Try new features without releasing

* use case-sensitive file name

* Refine

* Add highlighted rectangle in screenshot

* Add entrance in main readme

Author: qwordy

README.md

@@ -149,6 +149,12 @@ $ pip3 install --upgrade --pre azure-cli --extra-index-url https://azurecliprod.
 
 The edge build is generated for each PR merged to the `dev` branch as a part of the Azure DevOps Pipelines. 
 
+## Get builds of arbitrary commit or PR
+
+If you would like to get builds of arbitrary commit or PR, see:
+
+[Try new features before release](doc/try_new_features_before_release.md)
+
 ## Developer Setup
 
 If you would like to setup a development environment and contribute to the CLI, see:

doc/assets/1.PNG

@@ -0,0 +1,32 @@
+Try new features before release
+===
+
+This documentation shows how to try new features in commit or PR before release even if the PR is not merged.
+
+Azure CLI releases new versions every 3 weeks. Many customers and developers are eager to try and test new features before the formal release. Fortunately, Azure CLI project builds artifacts for every commit and PR and you can download them.
+
+## Tutorial for commit
+
+Step 1. Select a commit. Click the √ or × symbol. Click "Details" of a "build package" item.
+
+![](assets/1.PNG)
+
+Step 2. Click "View more details on Azure Pipelines".
+
+![](assets/2.PNG)
+
+Step 3. Click "1 artifact"
+
+![](assets/3.PNG)
+
+Step 4. Download your favorite artifact.
+
+![](assets/4.PNG)
+
+## Tutorial for PR
+
+Step 1. Open a PR no matter it is merged or not. Click "Checks" tab.
+
+![](assets/5.PNG)
+
+Step 2-4. Follow the same steps of tutorial for commit.