Fix: does not work on VSCode 1.47.0 and later

[MrRefactoring]

Fixes #143

I spent a couple of hours and figured out that everything works correctly on macOs. Then I opened this extension on Windows 10 and VSCode 1.47.2 in debugger mode and saw several errors that said that the path to the JavaScript files was incorrect. I took as a basis the path handling methods in this case from the vscode-azure-blockchain-ethereum repository

Tested on Windows 10 and macOs Catalina

As a workaround, you can use my hotfix extension: https://marketplace.visualstudio.com/items?itemName=mrrefactoring.polacode-fixed-edition