[DOCS] Updated release state for 7.0.0-alpha1 (#35596)

* [DOCS] Updated release state for 7.0.0-alpha1

* Update Versions.asciidoc

Author: debadair

docs/Versions.asciidoc

@@ -11,7 +11,7 @@
 release-state can be: released | prerelease | unreleased
 //////////
 
-:release-state:   unreleased
+:release-state:   prerelease
 
 :issue:           https://github.com/elastic/elasticsearch/issues/
 :pull:            https://github.com/elastic/elasticsearch/pull/