build(deps): update axllent/mailpit to v1.21.4

This MR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [axllent/mailpit](https://github.com/axllent/mailpit) | minor | `v1.20.7` -> `v1.21.4` |

MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot).

**Proposed changes to behavior should be submitted there as MRs.**

---

### Release Notes

<details>
<summary>axllent/mailpit (axllent/mailpit)</summary>

### [`v1.21.4`](https://github.com/axllent/mailpit/blob/HEAD/CHANGELOG.md#v1214)

[Compare Source](axllent/mailpit@v1.21.3...v1.21.4)

##### Bugfix

-   Fix external CSS stylesheet loading in HTML preview ([#&#8203;388](axllent/mailpit#388))

### [`v1.21.3`](https://github.com/axllent/mailpit/blob/HEAD/CHANGELOG.md#v1213)

[Compare Source](axllent/mailpit@v1.21.2...v1.21.3)

##### Chore

-   Update Go dependencies
-   Minor UI tweaks
-   Mute Dart Sass deprecation notices
-   Update node dependencies
-   Upgrade Alpine packages on Docker build
-   Add swagger examples & API code restructure

### [`v1.21.2`](https://github.com/axllent/mailpit/blob/HEAD/CHANGELOG.md#v1212)

[Compare Source](axllent/mailpit@v1.21.1...v1.21.2)

##### Feature

-   Add additional ignored flags to sendmail ([#&#8203;384](axllent/mailpit#384))

##### Chore

-   Remove legacy Tags column from message DB table
-   Update Go dependencies
-   Update node dependencies

##### Fix

-   Fix browser notification request on Edge ([#&#8203;89](axllent/mailpit#89))

### [`v1.21.1`](https://github.com/axllent/mailpit/blob/HEAD/CHANGELOG.md#v1211)

[Compare Source](axllent/mailpit@v1.21.0...v1.21.1)

##### Feature

-   Add ability to search by size smaller or larger than a value (eg: `larger:1M` / `smaller:2.5M`)
-   Add ability to search for messages containing inline images (`has:inline`)

##### Chore

-   Update Go dependencies
-   Separate attachments and inline images in download nav and badges ([#&#8203;379](axllent/mailpit#379))

### [`v1.21.0`](https://github.com/axllent/mailpit/blob/HEAD/CHANGELOG.md#v1210)

[Compare Source](axllent/mailpit@v1.20.7...v1.21.0)

##### Feature

-   Experimental Unix socket support for HTTPD & SMTPD ([#&#8203;373](axllent/mailpit#373))

##### Fix

-   Allow multiple item selection on macOS with Cmd-click  ([#&#8203;378](axllent/mailpit#378))

</details>

---

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---

This MR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
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chezmoi/dot_config/aquaproj-aqua/aqua.yaml

@@ -274,7 +274,7 @@ packages:
 - name: yassinebridi/[email protected]
   description: A simple terminal UI for search and replace, ala VS Code
   link: https://github.com/yassinebridi/serpl
-- name: axllent/mailpit@v1.20.7
+- name: axllent/mailpit@v1.21.4
   description: An email and SMTP testing tool with API for developers
   link: https://github.com/axllent/mailpit
 - name: mrjackwills/[email protected]