docs: hotfix docs dropdown: update versions.json reference in index.html (#108)

Author: LKasianAnsys

index.html

@@ -69,7 +69,7 @@
     <script>DOCUMENTATION_OPTIONS.pagename = 'index';</script>
     <script>
         DOCUMENTATION_OPTIONS.theme_version = '0.18.0';
-        DOCUMENTATION_OPTIONS.theme_switcher_json_url = '_static/versions.json';
+        DOCUMENTATION_OPTIONS.theme_switcher_json_url = 'https://visor.docs.pyansys.com/versions.json';
         DOCUMENTATION_OPTIONS.theme_switcher_version_match = '1.0';
         DOCUMENTATION_OPTIONS.show_version_warning_banner =
             false;