Build: Switch to use pnpm

[ndelangen]

The yarn lockfile seems near corruption somehow.
Could switch to yarn berry, or just take the dive into the future.

📦 Published PR as canary version: 0.0.4-canary.5.b0b42b9.0

✨ Test out this PR locally via:

npm install @chromaui/addon-visual-tests@0.0.4-canary.5.b0b42b9.0
# or 
yarn add @chromaui/addon-visual-tests@0.0.4-canary.5.b0b42b9.0

[ndelangen]

Someone should go visit the design-system packages and fix this:

└─┬ @storybook/design-system 7.15.11
  ├── ✕ unmet peer react@"^15.0.0 || ^16.0.0 || ^17.0.0": found 18.0.0
  ├── ✕ unmet peer react-dom@"^15.0.0 || ^16.0.0 || ^17.0.0": found 18.0.0
  └─┬ react-popper-tooltip 2.11.1
    ├── ✕ unmet peer react@^16.6.0: found 18.0.0
    ├── ✕ unmet peer react-dom@^16.6.0: found 18.0.0
    └─┬ react-popper 1.3.11
      └── ✕ unmet peer react@"0.14.x || ^15.0.0 || ^16.0.0 || ^17.0.0": found 18.0.0

[ndelangen]

This PR is not strictly necessary anymore if storybookjs/storybook#23080 lands and works as expected, but I'd propose still moving forward with it.. pnpm is a great package manager.

I understand it's annoying to have to run pnpm run XYZ instead of yarn XYZ, there's a lot of muscle-memory to overcome.