feat: Add workflow to update the aggregator

[bitdivine]

Motivation

We need to render SNS data accurately, so need to keep the aggregator SNS bindings up to date.

Changes

• Add a bot to update the SNS aggregator bindings regularly.
  • Note: If the candid API has not changed, no new PR will be created.
  • Note: The code is largely identical to the bot that updates the proposals bindings and generally matches all the other update bots.

Tests

• The one test run showed a breaking change that needed manual intervention. The run correctly posted the error in slack and I have made a PR with the manual changes.
• Run again and it correctly declared that no changes are needed: https://github.com/dfinity/nns-dapp/actions/runs/6863398505/job/18663096004

Todos

• Add entry to changelog (if necessary).

[lmuntaner]

LGTM! Just a minor comment