Create devcontainer.json

[Johnson1s]

pact-foundation#428

[tienvx]

I have some questions about this change:

• Can you explain a bit about that change? What benefits does it bring?
• This repo is just a fork. If you want to apply this change to more people (not just me), you have to create a PR to the original repo.
• Same as above point, the master branch is just a mirror of original repo's master branch. And I would like to keep them in sync. Can you change the target branch?
• Why you mention that compatibility suite's PR Implement V1 Consumer scenarios in this PR? That PR is quite old. And I don't see any relation.

[tienvx]

Closing as I don't see any benefits this bring. Please reopen when this PR is ready.