docs: mention Renovate installation (#137)

Author: JoshuaKGoldberg

README.md

@@ -36,6 +36,7 @@ It sets up the following tooling for you:
 - [**pnpm**](https://pnpm.io): Desk-efficient package manager alternative.
 - [**Prettier**](https://prettier.io): Opinionated formatting for code, run on file save and as a Git commit hook via [husky](https://typicode.github.io/husky) and [lint-staged](https://github.com/okonet/lint-staged).
 - [**release-it**](https://github.com/release-it/release-it): Generates changelogs, bumps the package version, and publishes to GitHub and npm based on [conventional commits](https://www.conventionalcommits.org).
+- [**Renovate**](https://docs.renovatebot.com): Keeps dependencies up-to-date with PRs, configured to wait a few days after each update for safety.
 - [**ts-prune**](https://github.com/nadeesha/ts-prune): Unused exports detection for TypeScript code.
 - [**TypeScript**](https://typescriptlang.org): A typed superset of JavaScript, configured with strict compiler options.
 - [**Vitest**](https://vitest.dev): Fast unit tests, configured with coverage tracking.
@@ -57,6 +58,7 @@ To use this template:
    - `NPM_TOKEN`: An [npm access token](https://docs.npmjs.com/creating-and-viewing-access-tokens/) with _Automation_ permissions
 4. `pnpm install`
 5. `pnpm run setup`
+6. Install the [Renovate GitHub App](https://github.com/marketplace/renovate)
 
 > The setup script removes the `## Explainer` and `## Setup` from this README.md.