docs: remove unnecessary badges

[cbaker6]

New Pull Request Checklist

• I am not disclosing a vulnerability.
• I am creating this PR in reference to an issue.

Issue Description

The Snyk badge isn't applicable anymore as the Gemfile's were only used for Jazzy.

Related issue: #n/a

Approach

Remove Snyk badge.

TODOs before merging

• Add changes to documentation (guides, repository pages, in-code descriptions)

[parse-github-assistant]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[codecov]

Codecov Report

Merging #353 (0981130) into main (1ad9ec2) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #353   +/-   ##
=======================================
  Coverage   88.01%   88.02%           
=======================================
  Files         114      114           
  Lines       12209    12209           
=======================================
+ Hits        10746    10747    +1     
+ Misses       1463     1462    -1     

Impacted Files	Coverage Δ
Sources/ParseSwift/Coding/ParseEncoder.swift	77.31% <0.00%> (-0.46%)	⬇️
Sources/ParseSwift/Objects/ParseObject.swift	85.03% <0.00%> (+0.15%)	⬆️
Sources/ParseSwift/LiveQuery/ParseLiveQuery.swift	76.58% <0.00%> (+0.58%)	⬆️

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