idb.info(): use seqStore.openKeyCursor() in place of openCursor() (#8763)

Request success handler is only using the key from the returned cursor, so an
IDBCursor instance is sufficient.

Author: alxndrsn

packages/node_modules/pouchdb-adapter-idb/src/index.js

@@ -411,7 +411,7 @@ function init(api, opts, callback) {
     txn.objectStore(META_STORE).get(META_STORE).onsuccess = function (e) {
       docCount = e.target.result.docCount;
     };
-    txn.objectStore(BY_SEQ_STORE).openCursor(null, 'prev').onsuccess = function (e) {
+    txn.objectStore(BY_SEQ_STORE).openKeyCursor(null, 'prev').onsuccess = function (e) {
       var cursor = e.target.result;
       updateSeq = cursor ? cursor.key : 0;
     };