Changes needed to work with jina 2.0.13 (python 3.9)

[tommykoctur]

I have get wikipedia-sentences working with jina 2.0.13. Feel free to edit if you want.

[jakobkruse1]

Thank you for your contribution.
We are currently reworking our examples more generally, we want to update them to use the latest jina version and containerize all executors. We will check if your contribution helps us with that. @nan-wang

[tommykoctur]

Thank you for the information. I think that in the meantime it could help newbies to run this particular example.

[nan-wang]

LGTM👍

[nan-wang]

recheckcla

[nan-wang]

Jina CLA check

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I have read the CLA Document and I hereby sign the CLA

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[nan-wang]

hmmm, we can't merge this PR at the current stage because the unit tests failed @tommykoctur