"Could not migrate the project!" To NS6

@jorugit commented on Wed Jul 03 2019

Environment
Provide version numbers for the following components (information can be retrieved by running tns info in your project folder or by inspecting the package.json of the project):
√ Component nativescript has 6.0.0-2019-07-02-133207-13547 version and is up to date.
√ Component tns-core-modules has 5.4.3 version and is up to date.
√ Component tns-android has 5.4.0 version and is up to date.
√ Component tns-ios has 5.4.2 version and is up to date.

Describe the bug
install the 6.0 RC with npm install -g nativescript@rc
and running "tns migrate": I got th following error:
Backup project configuration.
Backup project configuration complete.
Backup auto-generated files.
Backup auto-generated files complete.
Clean old project artefacts.
Could not migrate the project!

首先，使用 NativeScript 6.0 RC 和 issue 中列出的组件版本复现 tns migrate。清理旧的项目构件后，跟踪迁移步骤；当项目成功迁移且未报告“Could not migrate the project!”时，即表示完成。