[FEAT] Add new `fail_on_warnings` to the `coding-standard` action

[damienwebdev]

💡 Feature request

Feature Name

Allow Codesniff warnings

The Desired Behavior

As a developer, when I have PHPCS warnings, I don't necessarily want my CI pipeline to error. I would like something like:

fail_on_warnings:
    description: 'Whether action should fail on warnings or not, default to true (fails)'
    required: false

as an input to this action.

Your Use Case

As a developer, I want my ci pipeline to pass if there are PHPCS warnings but no errors.

[vitaliy-golomoziy]

PR for this issue: #132