Prep 'storage-1.5.0' release.

[tseaver]

Draft release notes:

google-cloud-storage 1.5.0

Features

• Add header enabling gzip downloads. (Add header enabling gzip downloads #3380)
• Bucket.user_project support: APIs for such buckets and their blobs are billed to the specified project. (Re-enable 'Bucket.requester_pays' feature #4056)
• Bucket.requester_pays property: requires that operations in the bucket be made with user_project set. (Re-enable 'Bucket.requester_pays' feature #4056)
• Add support for publishing notifications of bucket / blob operations to google.cloud.pubsub topics. (Add support for bucket notifications #4127)
• Validate checksums during download: when a validation error is detected, delete corrupt file. (Catch checksum validation failure from download, delete corrupt file #4133)

[dhermes]

@tseaver Can you expand on "Bucket notifications -> google.cloud.pubsub topics."

[dhermes]

Also I think the checksum validation should be a feature. We are adding something which didn't exist before. (Removing the file was added at the same time checksum validation was enabled.)

[tseaver]

Blocked on #4200.

[dhermes]

@tseaver This release does not need to be blocked by #4200.

[dhermes]

Especially considering our docs only appear as latest (i.e. there is no version of docs pinned to the Storage release).

If we were worried about blocking a release, this would be more concerning:
googleapis/google-resumable-media-python#34

[tseaver]

#4200 is awaiting closure from @frankyn, who is also the driver for getting the other storage features out.

[dhermes]

@tseaver I realize, but it's just documentation and does not need to block a release.

[lukesneeringer]

I would like @frankyn to make that decision. I have asked him to weigh in here.

Frank, if you think this should be blocked on #4200, could you provide us with an estimated time of resolution for #4200? If you think this can go ahead, then please give @tseaver an all clear.

Thanks!

[frankyn]

I reached out to the GCS team about the deprecation question and pending. I cc'd @lukesneeringer on it and will update #4200.

As for this PR. I don't think this release should be blocked on this open question given the operations still work at this time. Continue with this release but don't include PR #4200.