Update README.md (#1972)

Update the README to include the Contributor License Agreement as part of the Microsoft Open Source Code of Conduct.

README.md

@@ -179,6 +179,19 @@ Read more at [Building, Debugging and Sideloading the extension in Visual Studio
 
 This extension uses a host of Go tools to provide the various rich features. These tools are installed in your GOPATH by default. If you wish to have the extension use a separate GOPATH for its tools, provide the desired location in the setting `go.toolsGopath`. Read more about this and the tools at [Go tools that the Go extension depends on](https://github.com/Microsoft/vscode-go/wiki/Go-tools-that-the-Go-extension-depends-on).
 
+# Contributing
+
+This project welcomes contributions and suggestions.  Most contributions require you to agree to a
+Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us
+the rights to use your contribution. For details, visit https://cla.microsoft.com.
+
+When you submit a pull request, a CLA-bot will automatically determine whether you need to provide
+a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions
+provided by the bot. You will only need to do this once across all repos using our CLA.
+
+This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/).
+For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or
+contact [opencode@microsoft.com](mailto:opencode@microsoft.com) with any additional questions or comments.
 
 ## License
 [MIT](LICENSE)