PostCSS in Node.js 12+ throws DeprecationWarning

[nelsonni]

Describe the bug
In recent versions of Synectic, the following warning is thrown during compilation:

yarn start
yarn run v1.22.10
$ electron-forge start
✔ Checking your system
✔ Locating Application
✔ Preparing native dependencies
✔ Compiling Main Process Code
✔ Launch Dev Servers
✔ Compiling Preload Scripts
✔ Launching Application


Webpack Output Available: http://localhost:9000

⠹ Compiling Renderer Code(node:12168) [DEP0148] DeprecationWarning: Use of deprecated folder mapping "./" in the "exports" field module resolution of the package at /Users/nelsonni/Workspace/synectic/node_modules/postcss/package.json.
Update this package.json to use a subpath pattern like "./*".
(Use `node --trace-deprecation ...` to show where the warning was created)

To Reproduce
Steps to reproduce the behavior:

1. Run yarn start
2. Observe warning message in the console.

Expected behavior
Synectic is successfully able to compile in spite of this warning, but the expected behavior is that all dependencies conform to the underlying standards within their own dependencies.

Screenshots
N/A

Versions (please complete the following information):

• OS: MacOS, Windows, Linux
• Synectic Version: 1.0.0-beta (branch: development)

Additional context
Per postcss/postcss#1456, this issue was resolved in postcss v8.1.5. Therefore, updating any packages that use postcss so that the versions are above that threshold will allow us to resolve this issue. The following results appear when running yarn why postcss:

yarn why postcss
yarn why v1.22.10
[1/4] 🤔  Why do we have the module "postcss"...?
[2/4] 🚚  Initialising dependency graph...
[3/4] 🔍  Finding dependency...
[4/4] 🚡  Calculating file sizes...
=> Found "postcss@8.2.8"
info Reasons this module exists
   - "css-loader" depends on it
   - Hoisted from "css-loader#postcss"
info Disk size without dependencies: "340KB"
info Disk size with unique dependencies: "1.3MB"
info Disk size with transitive dependencies: "1.3MB"
info Number of shared dependencies: 3
✨  Done in 0.32s.