[Force upgrade] Define app config schema for GitHub pages endpoint

[owencraston]

Description

• builds off the work in this PR

• define the schema for app config object that will host the minimum app version and potentially other things

• I suggest we change the name of this file from minAppConfig.json to AppConfig.json or something that is more generic

• other suggestions were to add a feature flag field

• the current endpoint is https://metamask.github.io/metamask-mobile/minAppConfig.json

Acceptance Criteria

• we can fetch the hosted json object and see all the fields

Process (adapt per story)

• [ ] User research / data
• [ ] Ideation / Kickoff in cross-functional team
• [ ] Pattern research in mobile (crypto / non-crypto space)
• [ ] Proof of concept to check technical feasibility (if applicable)
• [ ] Design reviews with PM, Engineer(s)
• [ ] User testing
• [ ] Design - Dev handoff
• [x] Implementation
• [x] Code review
• [ ] Stakeholder review on latest build on iOS and Android
• [ ] QA - unit test, e2e tests, regression testing

[owencraston]

We could also consider using a GraphQl object to get better type support. This might be overkill since we would not benefit from the individual field fetching.

[owencraston]

This is my proposed schema

changed the file name to appConfig.json with the following schema

{
  "security": {
    "app_minimum_build": 700,
    "apple_minimum_os": 6,
    "android_minimum_api_level": 21
  },
  "featureFlags": []
}

@sethkfman what do you think?

[sethkfman]

What you do think about adding a version? @owencraston

{
  "security": {
    "app_minimum_build": 700,
    "apple_minimum_os": 6,
    "android_minimum_api_level": 21
  },
  "featureFlags": [],
  "version": "x.x.x"
}

[owencraston]

for versioning I suggest we put them into folders like this

// metamask-mobile/AppConfig/v1/AppConfig.json
{
  "security":{
    "minimumVersions": {
      "appMinimumBuild": 700,
      "appleMinimumOS": 6,
      "androidMinimumAPIVersion": 21
    }
  }
}