frontend-plugin-api: refactor extension "at" option to "attachTo"

Co-authored-by: Camila Belo <camilaibs@gmail.com>
Co-authored-by: Fredrik Adelöw <freben@gmail.com>
Co-authored-by: Vincenzo Scamporlino <vincenzos@spotify.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/graphiql/src/alpha.tsx

@@ -86,7 +86,7 @@ export function createEndpointExtension<TConfig extends {}>(options: {
 }) {
   return createExtension({
     id: `apis.plugin.graphiql.browse.${options.id}`,
-    at: 'apis.plugin.graphiql.browse/endpoints',
+    attachTo: { id: 'apis.plugin.graphiql.browse', input: 'endpoints' },
     configSchema: options.configSchema,
     disabled: options.disabled ?? false,
     output: {