Fix AnimatedSprite.textures type annotation

[ash-r1]

Description of change

I met an incorrect type definition for PIXI.AnimatedSprite's textures setter. on 5.3.x.
I realized annotation is different from a real .ts code, so I just adjusted.

Pre-Merge Checklist

• Lint process passed (npm run lint)
• Tests passed (npm run test)

I don't know which base branch is better to be merged.
but I expect this PR will be merged into 5.3.x and release as 5.3.8 or later.

btw, I read CONTRIBUTING.md but there is no master branch anymore. Is it (a little bit) outdated?

[codecov-io]

Codecov Report

Merging #7143 (9cd3e5c) into v5.3.x (dacad3a) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            v5.3.x     #7143   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           17        17           
  Lines          704       704           
=========================================
  Hits           704       704           

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[bigtimebuddy]

Thank you for the fix @ash-r1 👍

[ash-r1]

@bigtimebuddy Thanks quick response! 😄

[bigtimebuddy]

I was in the middle of working on a few PRs :)

[bigtimebuddy]

Thank you @ash-r1, I also added a PR #7149 for those typos in the contributing doc.