Missing dependency on chai

[cameel]

Contract compilation fails, apparently due to chai being referenced in hardhat.config.js but not declared in package.json.

git clone https://github.com/brinktrade/brink-core
cd brink-core/
yarn install
npx hardhat compile

An unexpected error occurred:

Error: Cannot find module 'chai'
Require stack:
- /tmp/brink-core/hardhat.config.js
- /tmp/brink-core/node_modules/hardhat/internal/core/config/config-loading.js
- /tmp/brink-core/node_modules/hardhat/internal/cli/cli.js
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)
    at Module.require (node:internal/modules/cjs/loader:999:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (/tmp/brink-core/hardhat.config.js:3:14)
    at Module._compile (node:internal/modules/cjs/loader:1097:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1149:10)
    at Module.load (node:internal/modules/cjs/loader:975:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Module.require (node:internal/modules/cjs/loader:999:19) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    '/tmp/brink-core/hardhat.config.js',
    '/tmp/brink-core/node_modules/hardhat/internal/core/config/config-loading.js',
    '/tmp/brink-core/node_modules/hardhat/internal/cli/cli.js'
  ]
}