Add devcontainer config

[spenserblack]

For various reasons, I like to use GitHub Codespaces sometimes.

I can go into some more details if necessary, but here are the highlights:

• Contributors can use a GitHub Codespace (container on the cloud) and code with VS Code running in the browser
• Contributors can create a development container locally if they have Docker and an editor that supports dev containers

There are a few ways to use a codespace, but the easiest is probably going to be to just press , while viewing your repository on github.com.

Even without this config one can open a codespace with a default image, which I think has Go installed, but this can be used to ensure the proper version is installed and also guide users to certain files (the openFiles option).

[boyter]

Cheers. Something I think I need to investigate more for my own use actually.

[spenserblack]

I've been using them for a while, let me know if you have any questions 😄