update spanner emulator version to 1.5.41 in config.yml

[sters]

Blocked by #178

---

Why

To support IS_HIDDEN column. Related PR: #176

Tested in my local

Current version

Terminal#1

>>> docker run -p 19010:9010 -p 19020:9020 gcr.io/cloud-spanner-emulator/emulator:1.5.34
...

Terminal#2

>>> gcloud spanner instances create test-instance --config emulator-config --description test --configuration spanner-emulator
Creating instance...done.

>>> gcloud spanner databases create test-database --instance test-instance --configuration spanner-emulator
Creating database...done.

>>> SPANNER_EMULATOR_HOST=localhost:19010 spanner-cli -p emul -i test-instance -d test-database
Connected.
spanner> CREATE TABLE FullTextSearch (
      ->   ID INT64 NOT NULL,
      ->   Content STRING(2048) NOT NULL,
      ->   Content_Tokens TOKENLIST AS (TOKENIZE_FULLTEXT(Content)) HIDDEN,
      -> ) PRIMARY KEY(ID);
Query OK, 0 rows affected (0.05 sec)

spanner> select * from INFORMATION_SCHEMA.COLUMNS limit 1;
+---------------+--------------+----------------+-------------+------------------+----------------+-----------+-------------+--------------+--------------+-----------------------+-----------+---------------+-------------+---------------------+---------------+-----------------------------+-------------------------+-------------------------+
| TABLE_CATALOG | TABLE_SCHEMA | TABLE_NAME     | COLUMN_NAME | ORDINAL_POSITION | COLUMN_DEFAULT | DATA_TYPE | IS_NULLABLE | SPANNER_TYPE | IS_GENERATED | GENERATION_EXPRESSION | IS_STORED | SPANNER_STATE | IS_IDENTITY | IDENTITY_GENERATION | IDENTITY_KIND | IDENTITY_START_WITH_COUNTER | IDENTITY_SKIP_RANGE_MIN | IDENTITY_SKIP_RANGE_MAX |
+---------------+--------------+----------------+-------------+------------------+----------------+-----------+-------------+--------------+--------------+-----------------------+-----------+---------------+-------------+---------------------+---------------+-----------------------------+-------------------------+-------------------------+
|               |              | FullTextSearch | Content     | 2                | NULL           | NULL      | NO          | STRING(2048) | NEVER        | NULL                  | NULL      | COMMITTED     | NO          | NULL                | NULL          | NULL                        | NULL                    | NULL                    |
+---------------+--------------+----------------+-------------+------------------+----------------+-----------+-------------+--------------+--------------+-----------------------+-----------+---------------+-------------+---------------------+---------------+-----------------------------+-------------------------+-------------------------+
1 rows in set (19.29675ms)

There is no IS_HIDDEN column.

The new version

Terminal#1

>>> docker run -p 19010:9010 -p 19020:9020 gcr.io/cloud-spanner-emulator/emulator:1.5.41
...

Terminal#2

>>> gcloud spanner instances create test-instance --config emulator-config --description test --configuration spanner-emulator
Creating instance...done.

>>> gcloud spanner databases create test-database --instance test-instance --configuration spanner-emulator
Creating database...done.

>>> SPANNER_EMULATOR_HOST=localhost:19010 spanner-cli -p emul -i test-instance -d test-database
Connected.
spanner> CREATE TABLE FullTextSearch (
      ->   ID INT64 NOT NULL,
      ->   Content STRING(2048) NOT NULL,
      ->   Content_Tokens TOKENLIST AS (TOKENIZE_FULLTEXT(Content)) HIDDEN,
      -> ) PRIMARY KEY(ID);
Query OK, 0 rows affected (0.02 sec)

spanner> select * from INFORMATION_SCHEMA.COLUMNS limit 1;
+---------------+--------------+----------------+-------------+------------------+----------------+-----------+-------------+--------------+--------------+-----------+-----------------------+-----------+---------------+-------------+---------------------+---------------+-----------------------------+-------------------------+-------------------------+
| TABLE_CATALOG | TABLE_SCHEMA | TABLE_NAME     | COLUMN_NAME | ORDINAL_POSITION | COLUMN_DEFAULT | DATA_TYPE | IS_NULLABLE | SPANNER_TYPE | IS_GENERATED | IS_HIDDEN | GENERATION_EXPRESSION | IS_STORED | SPANNER_STATE | IS_IDENTITY | IDENTITY_GENERATION | IDENTITY_KIND | IDENTITY_START_WITH_COUNTER | IDENTITY_SKIP_RANGE_MIN | IDENTITY_SKIP_RANGE_MAX |
+---------------+--------------+----------------+-------------+------------------+----------------+-----------+-------------+--------------+--------------+-----------+-----------------------+-----------+---------------+-------------+---------------------+---------------+-----------------------------+-------------------------+-------------------------+
|               |              | FullTextSearch | Content     | 2                | NULL           | NULL      | NO          | STRING(2048) | NEVER        | false     | NULL                  | NULL      | COMMITTED     | NO          | NULL                | NULL          | NULL                        | NULL                    | NULL                    |
+---------------+--------------+----------------+-------------+------------------+----------------+-----------+-------------+--------------+--------------+-----------+-----------------------+-----------+---------------+-------------+---------------------+---------------+-----------------------------+-------------------------+-------------------------+
1 rows in set (5.197084ms)

There is a IS_HIDDEN column.