Bump pywemo version. Improves notifications for insight devices.

[pavoni]

Description:
That updates the library version to improve notifications for wemo insight switches. It turns on subscriptions for power useage changes. Thanks to @jumpkick for the detective work and contribution

#6001 adds additional support for more attributes, but since the version upgrade itself was simple and useful I thought it was worth adding this as an preliminary PR.

Related issue (if applicable):
fixes #3506

Pull request in home-assistant.github.io with documentation (if applicable): home-assistant/home-assistant.github.io#<home-assistant.github.io PR number goes here>

Example entry for configuration.yaml (if applicable):

Checklist:

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.github.io

If the code communicates with devices, web services, or third-party tools:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

If the code does not interact with devices:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• Tests have been added to verify that the new code works.

[mention-bot]

@pavoni, thanks for your PR! By analyzing the history of the files in this pull request, we identified @jaharkes, @balloob and @fabaff to be potential reviewers.