release notes for v0.28.0

[rvan...@google.com]

Note: We did not update to OpenTelemetry as previously announced.

https://github.com/google/go-cloud/releases/tag/v0.28.0

BREAKING CHANGES:

• secrets/azurekeyvault: Updated to latest Azure SDK.
• blob/azureblob: Updated to match recent breaking changes in the Azure packages (yes, again).
• pubsub/awssnssqs: Fixed BeforeSend to take a pointer to the SendMessageBatchRequestEntry struct, so that it can be modified.

blob

• memblob: Fixed bug where use of BeforeCopy callback would drop the actual copying.
• azureblob: Updated to match recent breaking changes in the Azure packages.

pubsub

• all: Simplified and improved batch sizing, should resolve issues with too-frequent polling in some situations.
• azurepubsub: Made ListenerTimeout configurable.
• gcppubsub and awssnssqs: Support lazy mode for Nack (where no explicit Nack is sent).
• awssnssqs: Fixed BeforeSend to take a pointer to the SendMessageBatchRequestEntry struct, so that it can be modified.

secrets

• secrets/azurekeyvault: Updated to latest Azure SDK. Use azidentity.NewDefaultAzureCredential.

sql

• gcp/cloudsql: Fixed IAM login.