Add severity setting to ERBLint rules

[mxriverlynn]

Description

This PR adds the ability to set a severity level in our custom ERBLint rules, through the use of the new SeveritySchema linter schema. The goal is to provide a configuration option for linters, allowing us to set the failure severity in a project's erb-lint.yml file. This will help us with cleaning up the deprecated components counter failures in dotcom, by allowing us to re-enable that rules but only warn about the failures, giving us time to clean up the issues in smaller PRs

For this PR, only the DeprecatetdComponentsCounter linter is using the new severity schema. Tests for the DeprecatetdComponentsCounter have been updated to ensure the severity is used as expected.

Integration

Does this change require any updates to code in production?

No change required, as the new setting is optional. Once we are ready, the following configuration in dotcom's erb-lint.yml file needs to be made:

  DeprecatedComponentsCounter:
-   enabled: false
+   enabled: true
+   severity: :info

Setting the Severity

The options for severity in ERBLint come from ERBLint::Utils::SeverityLevels in ERBLint, and include the following:

• :info
• :refactor
• :convention
• :warning
• :error
• :fatal

NOTE: With all other settings defaulted, only the :info severity appears to ignore the failures. setting this to :warning or any other level (including the default / removing the setting) causes it to treat linting issues as failures. This is possible to change by updating the github-lint step to include the following command-line option for ERBLint, however:

--fail-level SEVERITY        Minimum severity for exit with error code

For example: bin/bundle exec erblint --fail-severity :error should allow severity: :warning to still pass the CI step, while allowing :error and :fatal to fail the step. Without further testing, though, it's unknown how the default nil severity would behave.

Proof of Concept in dotcom

Using this branch, I ran two examples of erblint on dotcom. the first was with the severity set to :warning and the second set to :info, using this proof of concept PR in dotcom

• 🔴 severity: :warning https://janky.githubapp.com/71857737/output
• ✅ severity: :info https://janky.githubapp.com/71860174/output

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews

[changeset-bot]

🦋 Changeset detected

Latest commit: 3f473bc

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@primer/view-components	Patch

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[camertron]

What a fantastic idea, thank you @mxriverlynn!!