CI error at each release commit
After 1.12.0, there is a recurrent CI error at each release commit: https://app.circleci.com/pipelines/github/huggingface/datasets/8289/workflows/665d954d-e409-4602-8202-e678594d2946/jobs/51110

```
____________________ LoadTest.test_load_dataset_canonical _____________________
[gw0] win32 -- Python 3.6.8 C:\tools\miniconda3\python.exe

self = <tests.test_load.LoadTest testMethod=test_load_dataset_canonical>

    def test_load_dataset_canonical(self):
        scripts_version = os.getenv("HF_SCRIPTS_VERSION", SCRIPTS_VERSION)
        with self.assertRaises(FileNotFoundError) as context:
            datasets.load_dataset("_dummy")
        self.assertIn(
            f"https://raw.githubusercontent.com/huggingface/datasets/{scripts_version}/datasets/_dummy/_dummy.py",
>           str(context.exception),
        )
E       AssertionError: 'https://raw.githubusercontent.com/huggingface/datasets/1.14.0/datasets/_dummy/_dummy.py' not found in "Couldn't find a dataset script at C:\\Users\\circleci\\datasets\\_dummy\\_dummy.py or any data file in the same directory. Couldn't find '_dummy' on the Hugging Face Hub either: FileNotFoundError: Couldn't find file at https://raw.githubusercontent.com/huggingface/datasets/master/datasets/_dummy/_dummy.py"

tests\test_load.py:358: AssertionError
```

