cognitive_planning update to python3.x

[moneypi]

Description

📝 Please include a summary of the change.
I get some error when I run cognitive_planning in Python3.8, so I try to fix these errors.
But I can't download AVD_Minimal.zip(https://storage.googleapis.com/active-vision-dataset/AVD_Minimal.zip) ......

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• Documentation update
• TensorFlow 2 migration
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• A new research paper code implementation
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Tests

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[jaeyounkim]

@arsalan-mousavian Can you review this PR?

[jaeyounkim]

@moneypi This model is not maintained anymore, and Arsalan Mousavian(@arsalan-mousavian) has not responded yet. This model will be achieved at the end of October unless Arsalan can help.

[arsalan-mousavian]

Thanks for making changes for python3 compatibility.
LGTM