[@storybook/addon-a11y] remove typings provided by package directly

[gaetanmaisse]

Please fill in this template.

• Use a meaningful title for the pull request. Include the name of the package modified.
• Test the change in your own code. (Compile and run.)
• Add or edit tests to reflect the change. (Run with npm test.)
• Follow the advice from the readme.
• Avoid common mistakes.

Select one of these and delete the others:

If removing a declaration:

• Delete the package's directory.
• Add it to notNeededPackages.json.

--

@storybook/addon-a11y was migrated to TS in this PR storybookjs/storybook#5738 and it was released publically in 5.1.0 (and first published on npm registry in 5.1.1)

[typescript-bot]

@gaetanmaisse Thank you for submitting this PR!

🔔 @HyunSeob - please review this PR in the next few days. Be sure to explicitly select Approve or Request Changes in the GitHub UI so I know what's going on.

If no reviewer appears after a week, a DefinitelyTyped maintainer will review the PR instead.

[typescript-bot]

After 5 days, no one has reviewed the PR 😞. A maintainer will be reviewing the PR in the next few days and will either merge it or request revisions. Thank you for your patience!

[RyanCavanaugh]

The bot is confused; the CI failures need to be addressed

[gaetanmaisse]

CI error had nothing to see with my modification 🤷‍♂:

Error: Please delete all files in webpack-dev-middleware when adding it to notNeededPackages.json.
    at util_1.mapIter.p (/home/vsts/work/1/s/node_modules/types-publisher/src/tester/test-runner.ts:110:19)
    at Object.mapIter (/home/vsts/work/1/s/node_modules/types-publisher/src/util/util.ts:237:15)
    at mapIter.next (<anonymous>)
    at Object.runTests [as default] (/home/vsts/work/1/s/node_modules/types-publisher/src/tester/test-runner.ts:75:20)

@RyanCavanaugh Anyway, I rebased on master and everything is ok now. 🚀

[typescript-bot]

@gaetanmaisse One or more reviewers has requested changes. Please address their comments. I'll be back once they sign off or you've pushed new commits or comments. Thank you!

[typescript-bot]

🔔 @RyanCavanaugh - Thanks for your review of this PR! Can you please look at the new code and update your review status if appropriate?

[gaetanmaisse]

@RyanCavanaugh any news about this PR?