build(deps): Update django-anymail requirement from <15.0,>=13.0 to >=13.0,<16.0

[dependabot]

Updates the requirements on django-anymail to permit the latest version.

Release notes

Sourced from django-anymail's releases.

v15.0

Changelog

Changelog

Sourced from django-anymail's changelog.

v15.0

2026-04-18

Breaking changes

* Require **Django 5.0 or later** and Python 3.10 or later.
  (Thanks to `@terencehonles`_.)
Features

* **Resend:** Add support for inbound email. (Thanks to `@btimby`_.)
Fixes

* **Inbound:** Convert carriage return and line feed characters in attachment
  filenames to spaces for ESPs that parse them from invalid headers (e.g.,
  Postmark). (Thanks to `@BHSPitMonkey`_ for reporting the issue and providing
  an example.)


v14.0
-----

*2025-12-17*

This release improves handling of Unicode characters everywhere email messages
allow them, based on extensive testing on all supported ESPs. See
`International email <https://anymail.dev/en/stable/tips/international_email/#idna>`_
in the docs for more information. There are several new workarounds for ESP
bugs with non-ASCII characters, plus a handful of new errors to help you avoid
Unicode bugs Anymail can't work around.

This release also includes support for Django 6.0 (earlier versions worked,
but provoked deprecation warnings) and adds the much-requested ESP Mailtrap.

Breaking changes
</code></pre>
<p>(These changes don't affect the vast majority of Anymail users.)</p>
<ul>
<li>
<p><strong>International domain names:</strong> When sending email to a non-ASCII domain name,
use IDNA 2008 with UTS-46 pre-processing rather than obsolete IDNA 2003
encoding. This ensures email can be sent to newer domains enabled by IDNA 2008.</p>
<p>This change should make no difference for virtually all real-world email</p>
</li>
</ul>
<!-- raw HTML omitted -->
</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Commits</summary>

<ul>
<li><a href="https://github.com/anymail/django-anymail/commit/17acea06b9361c3cc4ab6d9678bd5aea45db80ff"><code>17acea0</code></a> Release 15.0</li>
<li><a href="https://github.com/anymail/django-anymail/commit/8ad9d6e7e463efb770e3440871a05f2be4249ddf"><code>8ad9d6e</code></a> Inbound: sanitize CRNL in ESP-parsed attachment filenames</li>
<li><a href="https://github.com/anymail/django-anymail/commit/a6339d6c65bed21bcfe28e3c7b9b4ada4a290263"><code>a6339d6</code></a> Upgrade actions versions</li>
<li><a href="https://github.com/anymail/django-anymail/commit/4626462d49512b0c423071a8a6fe43a9610ead8a"><code>4626462</code></a> Drop Django 4.x</li>
<li><a href="https://github.com/anymail/django-anymail/commit/2bcfd620d2f1fa6705a13ad8645aa25a4572fd08"><code>2bcfd62</code></a> Resend: Add inbound support</li>
<li><a href="https://github.com/anymail/django-anymail/commit/13a08718571ca853f04336e15c525a98dd6dc48a"><code>13a0871</code></a> Run pyupgrade</li>
<li><a href="https://github.com/anymail/django-anymail/commit/7bf7a1a42e7fe1dbc008d22dc6d03579e4523b34"><code>7bf7a1a</code></a> Drop Django 4.0--4.2, Python 3.8--3.9 support</li>
<li><a href="https://github.com/anymail/django-anymail/commit/e0f50c2550a1f42e287ab63ca0046ba200e77353"><code>e0f50c2</code></a> Release 14.0</li>
<li><a href="https://github.com/anymail/django-anymail/commit/a575bfcf3ad9fc6ae48953d78d5dcee1b2fa75a9"><code>a575bfc</code></a> Docs: update some outdated examples</li>
<li><a href="https://github.com/anymail/django-anymail/commit/d6e837457a878088d0b96acea44af96b66244925"><code>d6e8374</code></a> CI/CD: reduce permissions to GitHub workflows</li>
<li>Additional commits viewable in <a href="https://github.com/anymail/django-anymail/compare/v13.0...v15.0">compare view</a></li>
</ul>
</details>

&lt;br /&gt;</code></pre>


Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`.

[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)

---

<details>
<summary>Dependabot commands and options</summary>
<br />

You can trigger Dependabot actions by commenting on this PR:
- `@dependabot rebase` will rebase this PR
- `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it
- `@dependabot show <dependency name> ignore conditions` will show all of the ignore conditions of the specified dependency
- `@dependabot ignore this major version` will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this minor version` will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)


</details>