chore: add DatasetListItem type (#1017)

_Thank_ you for opening a Pull Request! Before submitting your PR, there are a few things you can do to make sure it goes smoothly:
- [ ] Make sure to open an issue as a [bug/issue](https://github.com/googleapis/python-bigquery/issues/new/choose) before writing your code!  That way we can discuss the change, evaluate designs, and agree on the general idea
- [ ] Ensure the tests and linter pass
- [ ] Code coverage does not decrease (if any source code was changed)
- [ ] Appropriate docs were updated (if necessary)

Fixes #995 🦕

Author: steffnay

google/cloud/bigquery/client.py

@@ -549,7 +549,7 @@ def _dataset_from_arg(self, dataset):
 
     def create_dataset(
         self,
-        dataset: Union[str, Dataset, DatasetReference],
+        dataset: Union[str, Dataset, DatasetReference, DatasetListItem],
         exists_ok: bool = False,
         retry: retries.Retry = DEFAULT_RETRY,
         timeout: float = DEFAULT_TIMEOUT,
@@ -679,7 +679,7 @@ def create_routine(
 
     def create_table(
         self,
-        table: Union[str, Table, TableReference],
+        table: Union[str, Table, TableReference, TableListItem],
         exists_ok: bool = False,
         retry: retries.Retry = DEFAULT_RETRY,
         timeout: float = DEFAULT_TIMEOUT,
@@ -693,6 +693,7 @@ def create_table(
             table (Union[ \
                 google.cloud.bigquery.table.Table, \
                 google.cloud.bigquery.table.TableReference, \
+                google.cloud.bigquery.table.TableListItem, \
                 str, \
             ]):
                 A :class:`~google.cloud.bigquery.table.Table` to create.
@@ -1295,7 +1296,7 @@ def update_table(
 
     def list_models(
         self,
-        dataset: Union[Dataset, DatasetReference, str],
+        dataset: Union[Dataset, DatasetReference, DatasetListItem, str],
         max_results: int = None,
         page_token: str = None,
         retry: retries.Retry = DEFAULT_RETRY,
@@ -1372,7 +1373,7 @@ def api_request(*args, **kwargs):
 
     def list_routines(
         self,
-        dataset: Union[Dataset, DatasetReference, str],
+        dataset: Union[Dataset, DatasetReference, DatasetListItem, str],
         max_results: int = None,
         page_token: str = None,
         retry: retries.Retry = DEFAULT_RETRY,
@@ -1449,7 +1450,7 @@ def api_request(*args, **kwargs):
 
     def list_tables(
         self,
-        dataset: Union[Dataset, DatasetReference, str],
+        dataset: Union[Dataset, DatasetReference, DatasetListItem, str],
         max_results: int = None,
         page_token: str = None,
         retry: retries.Retry = DEFAULT_RETRY,
@@ -1525,7 +1526,7 @@ def api_request(*args, **kwargs):
 
     def delete_dataset(
         self,
-        dataset: Union[Dataset, DatasetReference, str],
+        dataset: Union[Dataset, DatasetReference, DatasetListItem, str],
         delete_contents: bool = False,
         retry: retries.Retry = DEFAULT_RETRY,
         timeout: float = DEFAULT_TIMEOUT,