Stacker

- address breaking moto change to awslambda [GH-763]
- Added Python version validation before update kms decrypt output [GH-765]

- Fixing AMI lookup Key error on 'Name'
- hooks: lambda: allow uploading pre-built payloads [GH-564]
- Ensure that base64 lookup codec encodes the bytes object as a string [GH-742]
- Use CloudFormation Change Sets for `stacker diff`
- Locked stacks still have requirements [GH-746]
- change diff to use CFN change sets instead of comparing template dicts [GH-744]
- Add YAML environment file support [GH-740]
- fix `stack.set_outputs` not being called by diff if stack did not change [GH-754]
- Fix python 2.7/3.5 dependency issue
- add cf notification arns [GH-756]

- Additional ECS unit tests [GH-696]
- Keypair unit tests [GH-700]
- Jinja2 templates in plain cloudformation templates [GH-701]
- Custom log output formats [GH-705]
- Python 3.7 unit tests in CircleCI [GH-711]
- Upload blueprint templates with bucket-owner-full-control ACL [GH-713]
- Change test runner from nose to py.test [GH-714]
- support for importing a local public key file with the keypair hook [GH-715]
- support for storing private keys in SSM parameter store with the keypair hook [GH-715]

- New lookup format/syntax, making it more generic [GH-665]
- Allow lowercase y/Y when prompted [GH-674]
- Local package sources [GH-677]
- Add `in_progress` option to stack config [GH-678]
- Use default ACL for uploaded lambda code [GH-682]
- Display rollback reason after error [GH-687]
- ssm parameter types [GH-692]

The big feature in this release is the introduction of "targets" which act as
sort of "virtual nodes" in the graph. It provides a nice way to logically group
stacks.

- Add support for "targets" [GH-572]
- Fix non-interactive changeset updates w/ stack policies [GH-657]
- Fix interactive_update_stack calls with empty string parameters [GH-658]
- Fix KMS unicode lookup in python 2 [GH-659]
- Locked stacks have no dependencies [GH-661]
- Set default profile earlier [GH-662]
- Get rid of recursion for tail retries and extend retry/timeout [GH-663]

This is a minor bugfix release for 1.4.0, no major feature updates.

As of this release python 3.5+ support is no longer considered experimental, and should be stable.

Special thanks to troyready for this release, I think most of these PRs were his :)

- allow raw cfn templates to be loaded from remote package\_sources [GH-638]
- Add missing config keys to s3 package source model [GH-642]
- Account for UsePreviousValue parameters in diff [GH-644]
- fix file lookup documented and actual return types [GH-646]
- Creates a memoized provider builder for AWS [GH-648]
- update git ref to explicitly return string (fix py3 bytes error) [GH-649]
- Lock botocore/boto to versions that work with moto [GH-651]