fixed ResourceConflictException when Uploading

[rriifftt]

when I Upload My Function to Lambda, following Exception Occured.

botocore.errorfactory.ResourceConflictException: An error occurred (ResourceConflictException) when calling the UpdateFunctionConfiguration operation: The operation cannot be performed at this time. An update is in progress for resource: arn:aws:lambda:region:account_id:function:my_function

This may be due to a change in the lambda specification.
https://aws.amazon.com/jp/blogs/compute/tracking-the-state-of-lambda-functions/

so I Trying to fix this issue. Just Added waiter for upload.py.
Please Review this 🙏

[rriifftt]

@jarosser06 No longer under maintenance?

[RyPoints]

I also see this error, but Rift's version didn't fix it.

[rriifftt]

@RyPoints same exception occurd?
me and my colleagues could avoided that exception by this version..

[odeckmyn]

@RyPoints same exception occurd?
me and my colleagues could avoided that exception by this version..

Had another issue in my use case. Check my PR, I've reused your brilliant wait code for the publish action that was broken for me.

[gdelvalle]

closing in favor of #170