fix: typo of PlacePhoto::photo_reference

[NickCis]

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• Make sure to open a GitHub issue as a bug/feature request before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea
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Fixes #346 🦕

[codecov]

Codecov Report

Merging #347 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #347   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files          21     21           
  Lines         326    326           
  Branches       84     84           
=====================================
  Hits          326    326

Impacted Files	Coverage Δ
src/common.ts	100% <ø> (ø)	⬆️

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[jpoehnelt]

🎉 This PR is included in version 2.1.2 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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