"sam deploy" does not execute if a tag has a long value

Description: The sam deploy command hangs if a tag with a long value (approx 30+ characters long) is provided. Tested on SAM CLI v0.43.0.

Steps to reproduce the issue:

1. Create an empty directory and navigate to it.
2. Execute sam deploy --stack-name test --tags key=012345678901234567890123456789

Observed result: The command hangs and does not produce any output.

Expected result:

	Deploying with following values
	===============================
	Stack name                 : test
	Region                     : None
	Confirm changeset          : False
	Deployment s3 bucket       : None
	Capabilities               : null
	Parameter overrides        : {}

Initiating deployment
=====================
Error: Failed to package template: /tmpDir/template.yml. 
 [Errno 2] No such file or directory: '/tmpDir/template.yml'

However, if a shorter tag value is provided (e.g. sam deploy --stack-name test --tags key=01234567890123456789) then the correct output gets printed.

[beck3905]

This appears to be caused by this regex that was added in version 0.42.0: https://github.com/awslabs/aws-sam-cli/blob/develop/samcli/cli/types.py#L207.

I isolated this code and tried it with a short tag and a long tag and it is the re.findall call that is hanging. Not exactly sure what the regex pattern is meant to do as it is a rather long and complex pattern. A little more commenting for that would be helpful.

[dslove]

In my case there is no any error msg showing up. It took me a day to figure out what the problem is and it was because I was lucky to google and find this page… I am using 0.44.