[ECR] [request]: Enhanced scanning, ability to initial a manual scan of an image.

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**Tell us about your request**
This request was submitted on behalf of a customer.

**Which service(s) is this request for?**
ECR

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**

For Images that aren’t pushed/updated for more than 30 days due to reasons like code freezes or no changes to push etc, the below [30day limitation](https://docs.aws.amazon.com/AmazonECR/latest/userguide/image-scanning-enhanced.html#image-scanning-enhanced-considerations) is preventing enhanced scanning to work for stale images.

```
When continuous scanning is enabled for a repository, if an image hasn't been updated in the past 30 days based on the image push timestamp, then continuous scanning is suspended for that image.
```
The design decision must have been to [save costs](https://aws.amazon.com/inspector/pricing/), as the re-scans triggered by continuous scan will include stale or obsolete images. However, an option to manually trigger an enhanced scan would be useful.

**Are you currently working around this issue?**
How are you currently solving this problem?

For use-cases where there are several stale (yet valid and operational) images across multiple regions/accounts, requires users to push images(to update timestamp), which might not be a best workaround or not practical in some cases.