Update README.md (#1207)

* Update README.md

Added troubleshooting section for install in Linux

* Update README.md

Author: tsuwandy

README.md

@@ -24,23 +24,26 @@ $ npm i -g @microsoft/botframework-cli
 $ bf
 ~~~
 
+## Troubleshooting
+
+For installation failures in some Linux platforms, try one of the following workarounds:
+- Upgrade npm to version 7.9
+- Install without the '-g' option and use [npx](https://www.npmjs.com/package/npx)
+
+~~~
+$ npm i @microsoft/botframework-cli
+$ npx bf
+~~~
+
 ## Available Commands
+
 The following commands are currently available:
 * [Chatdown][1]
 * [Config][2]
 * [Dialog][3]
 * [Luis][4]
 * [QnAMaker][5]
 
-<!--
-Preview commands (Install running [bf plugins](https://github.com/microsoft/botframework-cli/tree/main/packages/plugins#microsoftbf-cli-plugins))
-* [Dialog](https://github.com/microsoft/botframework-cli/tree/main/packages/dialog)
--->
-
-#### Future Commands
-The following commands will be ported in upcoming releases:
-* Dispatch
-
 See [Porting Map](https://github.com/microsoft/botframework-cli/blob/main/PortingMap.md) for a mapping reference between old and new tools
 
 ## Overview