commitlint: body's lines must not be longer than 100 characters [body-max-line-length]

Dependabot commit messages body line lengths do not conform with `commitlint`'s defaults.

Take a look at https://github.com/felipecassiors/megatar/pull/13 and https://github.com/felipecassiors/megatar/pull/14

It fails with:

> ```log
> ⧗ input: build(deps-dev): bump @typescript-eslint/eslint-plugin
>
> Bumps [@typescript-eslint/eslint-plugin](https://github.com/typescript-eslint/typescript-eslint/tree/HEAD/packages/eslint-plugin) from 3.8.0 to 3.9.0.
> - [Release notes](https://github.com/typescript-eslint/typescript-eslint/releases)
> - [Changelog](https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/CHANGELOG.md)
> - [Commits](https://github.com/typescript-eslint/typescript-eslint/commits/v3.9.0/packages/eslint-plugin)
>
> Signed-off-by: dependabot[bot]
> ✖ body's lines must not be longer than 100 characters [body-max-line-length]
>
> ✖ found 1 problems, 0 warnings
> ⓘ Get help: https://www.conventionalcommits.org/
> ```

https://github.com/felipecassiors/megatar/pull/13/checks?check_run_id=969926394#step:4:19

Start by reproducing the commitlint failure shown in the linked Dependabot pull requests and compare the generated body with the 100-character rule. Trace the commit-message generation and commitlint configuration, then verify that Dependabot-generated messages pass the relevant check without the body-max-line-length error.

Written by the indexing model from the issue text.