Add "atlantis version" command

[mwarkentin]

It would be nice if you could run atlantis version which could run terraform version and return the output in a comment:

Terraform v0.12.30
+ provider.aws v3.37.0
+ provider.cloudflare v2.20.0
+ provider.dns v2.2.0
+ provider.sentry (unversioned)
+ provider.sumologic v2.9.2

Your version of Terraform is out of date! The latest version
is 0.15.1. You can update by downloading from https://www.terraform.io/downloads.html

This would be helpful for debugging and understanding the state of the remote system on atlantis. It could also enhance the output with the version of atlantis that's running as well. I suppose this would need to support projects -p <project> with atlantis version returning the output for all planned projects in the PR.

[paul-civitas]

Yes. As is it's very impractical to figure out what provider version atlantis is using!

[gluehbirnenkopf]

@mwarkentin issue can be closed

[divyeshramani]

getting error "InvalidParameterException: The specified filter pattern does not support dimensions" when adding dimesions to aws_cloudwatch_log_metric_filter. That is supported since aws provider version "3.44.0", so why is it not working. It would help a lot to know which AWS provider version is used by atlantis.