[Resolves #978] Only install typing on Python<3.5

[gabriellesc]

This PR constrains the installation of typing to Python<3.5, since it is included in the standard library as of 3.5 and causes issues if installed alongside the standard library version.

PR Checklist

• Wrote a good commit message & description [see guide below].
• Commit message starts with [Resolve #issue-number].
• Added/Updated unit tests.
• Added/Updated integration tests (if applicable).
• All unit tests (make test) are passing.
• Used the same coding conventions as the rest of the project.
• The new code passes flake8 (make lint) checks.
• The PR relates to only one subject with a clear title.
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• Before merge squash related commits.

Other Information

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[zaro0508]

maybe should just remove typing altogether since sceptre currently only supports python 3.6 and 3.7? https://github.com/Sceptre/sceptre/blob/master/tox.ini#L2

[chrono]

Anything else needed to merge this?

[ykhalyavin]

maybe should just remove typing altogether since sceptre currently only supports python 3.6 and 3.7? https://github.com/Sceptre/sceptre/blob/master/tox.ini#L2

Makes sense

[tarkatronic]

@gabriellesc Do you have time to update this and fully remove typing?

@zaro0508 If Gabrielle is not able to get this updated, would you be willing to merge another PR to take care of this? And would there be a possibility of a bugfix release to include this update?

This has become a hard blocker for me, as I cannot concurrently install sceptre and black into my projects.

[zaro0508]

@zaro0508 If Gabrielle is not able to get this updated, would you be willing to merge another PR to take care of this? And would there be a possibility of a bugfix release to include this update?

yes @tarkatronic, willing to merge another PR for this however we are having difficulties with making a release at this moment. we are having discussions and trying to resolve in the #sceptre slack channel.

[craighurley]

Hi @tarkatronic , to work around module conflicts I run sceptre in a container. If this is something that would work for you in this case, have a look at https://github.com/craighurley/docker-sceptre

[gabriellesc]

Fully removed the typing dependency as suggested! Let me know if there is anything I missed.