add support for configurable retry-count

[schmod]

Issue #, if available: #502

Description of changes:
Adds support for a configurable number of retries (particularly for rate-limit errors).

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If we were using aws-sdk-js V3, we'd be able to do this with environment variables, but that's probably a larger change than we want to make here, as there may be folks who are indirectly depending on features of the V2 SDK.

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closes #502

[schmod]

I've been running this on my fork for a few days, and it seems to work!

[schmod]

bump

[amazreech]

Hi @schmod,

Thank you for your Patience. We appreciate your contribution to the repository and will be working to review the changes in the Pull Request. We will reach-out if with any questions or suggestions during the review.

In the meantime please ensure that below steps, if not already completed, are taken care of in your Pull Request:

1. Verify if PR follows semantic pull request conventions.
   Example: please make sure the PR title follows the convention.

2. Please run npm run package command to update dist/ folder with latest dependencies.

3. Resolve any merge conflicts on the PR

[trivikr]

This PR needs to be rebased to use AWS SDK for JavaScript (v3) which uses maxAttempts

Refer: #529

[rantoniuk]

@amazreech really? After 6+ months you're asking the contributor to rebase? That's not how contributions are supposed to work.

Assuming the PR is valid and introduced a wanted new functionality, I'd expect that if the maintainers don't have the capacity to review within 1-2 months, then they should spend some time rebasing the PR themselves. After almost a year the contributor might be far away doing a totally different work! (yes, I maintain some repositories as well and this is exactly what I do).

[trivikr]

I'm not a maintainer of this repo, but a contributor like yourself. I just spent some time to go through other open PRs which were impacted because of my change, and commented on them.