Bump python-smarttub dependency to 0.0.28

[mdz]

Proposed change

Bump python-smarttub dependency from 0.0.27 to 0.0.28
mdz/python-smarttub@v0.0.27...v0.0.28

There are no functional changes, this release just validates compatibility with aiohttp 3.8.0 and relaxes the dependency accordingly

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• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
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[MartinHjelmare]

Thanks!