[eslint-plugin] Support ESLint 8

[Daniel (D4N14L)]

Summary

Updates the Rushstack repo to support and use ESLint v8 for linting.

Fixes#2890

cc Lukas (@lukashass)

Details

There are some aspects to this upgrade that deserve to be called out:

• @rushstack/tree-pattern is temporarily remaining on eslint@7.30.0. This is due to it's dependency on an older version of @rushstack/eslint-config/@rushstack/eslint-plugin since it consumes these packages as cyclic dependencies. Once the new packages are published and the cyclic dependencies are bumped, this project should be able to be updated to 8.3.0 and have the common-versions.json changes removed.
• @rushstack/eslint-config temporarily disables eslint-plugin-promise rules (of which there was only one). This is required since the package does not yet support ESLint v8 (see this issue: Support ESLint 8.x eslint-community/eslint-plugin-promise#218).

How it was tested

Build while consuming the new version of ESLint and the updated config/plugin in dependent projects.

[Ian Clanton-Thuon (iclanton)]

Can you add a project that continues to test ESLint 7?

[Ian Clanton-Thuon (iclanton)]

IIRC you mentioned that eslint-plugin-promise is just missing some manifest file. Can we add something in eslint-patch to fix that as a stopgap?

[Daniel (D4N14L)]

IIRC you mentioned that eslint-plugin-promise is just missing some manifest file. Can we add something in eslint-patch to fix that as a stopgap?

I would prefer not to go that route. The change on the eslint-plugin-promise is relatively minor, just taking a while to go through... on our side, we currently only consume one rule, and it's a pretty simple one (confusing resolve and reject callbacks). Patching for eslint to add a new feature is one thing... patching a rules package where we only consume 1 rule seems excessive. Especially since eslint-patch is now used by so many people: https://www.npmjs.com/package/@rushstack/eslint-patch

[Daniel (D4N14L)]

Ian Clanton-Thuon (@iclanton) I added a small test project, could you take a look to make sure that it's sufficient?