Fixing broken entity key link in quickstart

[adchia]

What this PR does / why we need it:
Fixes a broken link in the quickstart python notebook

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

NONE

[codecov-commenter]

Codecov Report

Merging #2068 (44c24ee) into master (380cc62) will decrease coverage by 0.28%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2068      +/-   ##
==========================================
- Coverage   83.59%   83.31%   -0.29%     
==========================================
  Files         100      100              
  Lines        8084     8084              
==========================================
- Hits         6758     6735      -23     
- Misses       1326     1349      +23     

Flag	Coverage Δ
integrationtests	73.74% <ø> (+0.02%)	⬆️
unittests	58.20% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
sdk/python/feast/infra/aws.py	72.59% <0.00%> (-11.06%)	⬇️

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[feast-ci-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: adchia, woop

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[woop]

/lgtm

[achals]

@adchia I think this needs to be rebased before it can get merged

[achals]

/lgtm