SDKs: Trigger build on upstream dependency change

## Problem

SDKs do _not_ pin several dependencies, which leads to builds breaking unexpectedly. Here are the floating dependencies:
* algorand-sdk-testing
* generator
* go-algorand
* indexer
* sandbox

We encountered a situation where changes in upstream dependencies broke SDK builds. Resolving the root issue cause took _days_ because it took time to triage _when_ the breaking change was introduced. Additionally, there were 2 (not 1) breaking changes. Related upstream changes:
* https://github.com/algorand/indexer/pull/1370 - Patched via https://github.com/algorand/indexer/pull/1380
* https://github.com/algorand/sandbox/issues/161

Consequently, the story requests installing build triggers based on upstream dependency changes.
* When one of the listed dependencies makes a change available (e.g. merge to known branch, release nightly artifact, etc), each SDK ought to run its build.
* The intent is to isolate a breaking change, which ought to simplify triaging efforts.

Alternatively, we can pin dependencies. Doing so involves process changes. Open to discussion provided the approach accounts for keeping dependencies up-to-date.

## Solution

## Dependencies

## Urgency