Add drf-sendables to third-party-packages.md (#9261)

Author: amikrop

docs/community/third-party-packages.md

@@ -125,6 +125,7 @@ To submit new content, [open an issue][drf-create-issue] or [create a pull reque
 
 ### Misc
 
+* [drf-sendables][drf-sendables] - User messages for Django REST Framework
 * [cookiecutter-django-rest][cookiecutter-django-rest] - A cookiecutter template that takes care of the setup and configuration so you can focus on making your REST apis awesome.
 * [djangorestrelationalhyperlink][djangorestrelationalhyperlink] - A hyperlinked serializer that can can be used to alter relationships via hyperlinks, but otherwise like a hyperlink model serializer.
 * [django-rest-framework-proxy][django-rest-framework-proxy] - Proxy to redirect incoming request to another API server.
@@ -157,6 +158,7 @@ To submit new content, [open an issue][drf-create-issue] or [create a pull reque
 * [drf-redesign][drf-redesign] - A project that gives a fresh look to the browse-able API using Bootstrap 5.
 * [drf-material][drf-material] - A project that gives a sleek and elegant look to the browsable API using Material Design.
 
+[drf-sendables]: https://github.com/amikrop/drf-sendables
 [cite]: http://www.software-ecosystems.com/Software_Ecosystems/Ecosystems.html
 [cookiecutter]: https://github.com/jpadilla/cookiecutter-django-rest-framework
 [new-repo]: https://github.com/new