Configure Renovate (#4)

Welcome to [Renovate](https://redirect.github.com/renovatebot/renovate)! This is an onboarding PR to help you understand and configure settings before regular Pull Requests begin.

🚦 To activate Renovate, merge this Pull Request. To disable Renovate, simply close this Pull Request unmerged.

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### Detected Package Files

 * `Cargo.toml` (cargo)
 * `.github/workflows/ci.yml` (github-actions)
 * `.github/workflows/lint.yml` (github-actions)
 * `.github/workflows/publish.yml` (github-actions)

### Configuration Summary

Based on the default config's presets, Renovate will:

  - Start dependency updates only once this onboarding PR is merged
  - Hopefully safe environment variables to allow users to configure.
  - Show all Merge Confidence badges for pull requests.
  - Enable Renovate Dependency Dashboard creation.
  - Use semantic commit type `fix` for dependencies and `chore` for all others if semantic commits are in use.
  - Ignore `node_modules`, `bower_components`, `vendor` and various test/tests (except for nuget) directories.
  - Group known monorepo packages together.
  - Use curated list of recommended non-monorepo package groupings.
  - Apply crowd-sourced package replacement rules.
  - Apply crowd-sourced workarounds for known problems with packages.

🔡 Do you want to change how Renovate upgrades your dependencies? Add your custom config to `renovate.json` in this branch. Renovate will update the Pull Request description the next time it runs.

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### What to Expect

With your current configuration, Renovate will create 1 Pull Request:

<details>
<summary>chore(deps): update dependency ubuntu to v24</summary>

  - Schedule: ["at any time"]
  - Branch name: `renovate/ubuntu-24.x`
  - Merge into: `main`
  - Upgrade [ubuntu](https://redirect.github.com/actions/runner-images) to `24.04`

</details>

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❓ Got questions? Check out Renovate's [Docs](https://docs.renovatebot.com/), particularly the Getting Started section.
If you need any further assistance then you can also [request help here](https://redirect.github.com/renovatebot/renovate/discussions).

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This PR was generated by [Mend Renovate](https://mend.io/renovate/). View the [repository job log](https://developer.mend.io/github/resend/resend-rust).

<!--renovate-config-hash:e80b4e42a3043bc12fa0640db4bac392d2bf770acf841360d7c8ceeeac2ec1a9-->

Author: renovate[bot]

renovate.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:recommended"
+  ]
+}