create_bucket expects a project even with an emulator "ValueError: Client project not set: pass an explicit project."

[oittaa]

Thanks for fixing #324. I just noticed that create_bucket still expects a project. Would it make sense that it'd also detect STORAGE_EMULATOR_HOST and use a "fake" project automatically like here?

Environment details

• OS type and version: MacOS 12.1
• Python version: python --version Python 3.9.9
• pip version: pip --version pip 21.3.1
• google-cloud-storage version: pip show google-cloud-storage 2.1.0

Steps to reproduce

1. See the example below.

Code example

import os

from google.cloud import storage

HOST = "localhost"
PORT = 9023
BUCKET = "test-bucket"

os.environ["STORAGE_EMULATOR_HOST"] = f"http://{HOST}:{PORT}"
client = storage.Client()

bucket = client.create_bucket(BUCKET)

Stack trace

Traceback (most recent call last):
  File "/Users/user/workspace/temp/test.py", line 12, in <module>
    bucket = client.create_bucket(BUCKET)
  File "/Users/user/workspace/temp/.venv/lib/python3.9/site-packages/google/cloud/storage/client.py", line 940, in create_bucket
    raise ValueError("Client project not set:  pass an explicit project.")
ValueError: Client project not set:  pass an explicit project.