Create devcontainer.json

[Slowwalkin]

Type of change (place an x in the [ ] that applies)

• [x] New sample
• [x] New feature
• [x] Bug fix
• [x] Documentation

Summary

Describe the goal of this PR. Mention any related Issue numbers.

If you are introducing a new sample app in this pull request, please also include a detailed description of the application’s purpose and functionality.

Requirements (place an x in each [ ] that applies)

• [x] I’ve checked my submission against the Samples Checklist to ensure it complies with all standards
• [x] I have ensured the changes I am contributing align with existing patterns and have tested and linted my code
• [x] I've read and agree to the Code of Conduct

[salesforce-cla[bot]]

Thanks for the contribution! Before we can merge this, we need @Slowwalkin to sign the Salesforce Inc. Contributor License Agreement.

[hello-ashleyintech]

hi, @Slowwalkin! Could I get some context behind this suggested change? It looks like you're trying to add a new config-type file, but since this is a template for anyone to use, we want to avoid adding any app-specific custom configs!

[zimeg]

Hey @Slowwalkin 👋 Thanks for poking at this! Devcontainers were unfamiliar to us, but after a bit of poking we found that the powers these hold are immense and cool.

We now include a .devcontainer packaged with the Slack CLI and the Deno runtime across all of our samples for quick development! 🚀 Hopefully this can be helpful but please callout anything that seems strange with it!