release notes for v0.26.0

[rvan...@google.com]

https://github.com/google/go-cloud/releases/tag/v0.26.0

all

• Updated to Go 1.19 (with compatibility for Go 1.18).

blob

• all: Made blob.Reader implement io.ReadSeekCloser.
• all: Added WriterOption.MaxConcurrency.
• azureblob: Fixed a capture bug in As for List.

pubsub

• gcppubsub: Exposed ReceivedMessage in As (for AckId)
• rabbitpubsub: Switch to using github.com/rabbitmq/amqp091-go.

runtimevar

• awsparamstore: Drop the DescribeParameters call, it's not needed.

sql

• gcp/cloudsql: Enable IAM login.