[Docs] Updating URL for Openstack Swift plugin (elastic#34136)

The repository plugin for Openstack Swift was developed originally by Wikimedia foundation but is now retired. This changes the link to the repo where the actively maintained fork lives now.

Author: synhershko

docs/plugins/repository.asciidoc

@@ -32,7 +32,7 @@ The GCS repository plugin adds support for using Google Cloud Storage service as
 
 The following plugin has been contributed by our community:
 
-* https://github.com/wikimedia/search-repository-swift[Openstack Swift] (by Wikimedia Foundation)
+* https://github.com/BigDataBoutique/elasticsearch-repository-swift[Openstack Swift] (by Wikimedia Foundation and BigData Boutique)
 
 
 include::repository-azure.asciidoc[]