Open tutorial README in Gitpod

[lgruen]

Only open the tutorial README file instead of restricting the view to the tutorials directory:

• This avoids reloading the workspace, which at least in the browser can cause a second confirmation prompt.
• It's nice to be able to browse the full code in the Explorer bar and jump to the right file from the tutorial. That's also why installing github.com/rogpeppe/godef is helpful, to jump directly to function definitions.

[gitpod-io]

[TimothyStiles]

Good points @lgruen! Merged.