Allow pulling versions with crossing-go

[danielc2013]

Add an option like crossing-go get --version $VERSION_ID to allow for pulling versions of files in S3

Relevant documentation: https://docs.aws.amazon.com/sdk-for-go/api/service/s3/#GetObjectInput
Spot to add the version: https://github.com/stelligent/crossing-go/blob/master/cmd/get.go#L76

Note:
This will also require changing the Maximum number of arguments allowed for the "get" command. You'll have to provide a flag and the VersionId which means the max number of arguments should be 4. Then, you'll have to change how the s3 url is detected. Instead of assuming it's at position 0 of the args.

Finally, consider adding some validation to the VersionId to make sure the input is correct