test_bucket_listv2_encoding_basic

Hi,
about test `test_bucket_listv2_encoding_basic` (full name: `s3tests_boto3.functional.test_s3:test_bucket_listv2_encoding_basic`)
It is written in the [documentation](https://docs.aws.amazon.com/AmazonS3/latest/API/API_ListObjectsV2.html#API_ListObjectsV2_ResponseSyntax:~:text=Type%3A%20String-,EncodingType,-Encoding%20type%20used):

> If you specify the encoding-type request parameter, Amazon S3 includes this element in the response, and returns encoded key name values in the following response elements:
> Delimiter, Prefix, Key, and StartAfter.

```diff
- `eq(response['Delimiter'], '/')`
+ `eq(response['Delimiter'], '%2F')`
```

```diff
- `eq(prefixes, ['foo%2B1/', 'foo/', 'quux%20ab/'])`
+ `eq(prefixes, ['foo%2B1%2F', 'foo%2F', 'quux%20ab%2F'])`
```
(the '/' after encoding).

In case the above is true, please let me know. I can create a PR with the fix.