feat: Add usage example for monitoring alerts on KMS key versions

[romanini-ciandt]

The goal of this PR is to provide an example of an alert being sent when a KMS key version is marked to be deleted.

[tdbhacks]

This is extremely cool, nicely done!!

I guess my only comment is that maybe it's worth to also offer a version (through another input variable) where the module doesn't necessarily create a new key version. But I guess this is an example and not a true standalone module, so feel free to ignore. I imagine one of the reasons to have it in there was to also make testing easier in terms of having a sample key ready to be destroyed, otherwise that part would have to be in the test logic itself. Other than that, LGTM!

We'll see if @erlanderlo has more to say :)

[erlanderlo]

lgtm - good testing ideas.
mostly nits and few minor comments

[romanini-ciandt]

This is extremely cool, nicely done!!

I guess my only comment is that maybe it's worth to also offer a version (through another input variable) where the module doesn't necessarily create a new key version. But I guess this is an example and not a true standalone module, so feel free to ignore. I imagine one of the reasons to have it in there was to also make testing easier in terms of having a sample key ready to be destroyed, otherwise that part would have to be in the test logic itself. Other than that, LGTM!

We'll see if @erlanderlo has more to say :)

Thanks for your review!
Yeah, I'm creating the key in the example in order to get the testing process easier and more effective (because we can actually delete the key that was previously created and test the expected result.)

I added a comment with instructions for users wanting to use an existing KMS key.

[romanini-ciandt]

@apeabody could you PTAL on this PR?
It's approved by @erlanderlo. If you don't have any additional point, we'd like to merge it, please.

[apeabody]

Already reviewed