Implement message attribute parsing for PublishBatch

Factor out attribute parsing for SendMessage, SendMessageBatch, and Publish in the process.

I believe this change is adequately covered by the smoke tests, but am
happy to be convinced otherwise

Refactor MessageAttributes

added confirm subscription

update

udpate

fixed

update

chore(release): build multi-arch docker image with same suffix

While trying to migrate workloads from amd64 to arm64, having a single tag
for both architectures makes the transition easier.

Reference: https://goreleaser.com/cookbooks/multi-platform-docker-images/#creating-multi-platform-docker-images-with-goreleaser

Fix 1.1.x releases and update builder

format the go.mod

Add release testing action

Fix default config once and for all

Add arm64 docker build

Harden release workflow