feat: Add missing become() type methods

[cbaker6]

New Pull Request Checklist

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

Issue Description

The become() type method is currently not available to use for async/await and Combine.

Approach

Add the missing methods and have them call their completion handler counterpart.

TODOs before merging

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

[codecov]

Codecov Report

Merging #66 (f5b8650) into main (ed55608) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main      #66   +/-   ##
=======================================
  Coverage   90.45%   90.46%           
=======================================
  Files         166      166           
  Lines       14942    14952   +10     
=======================================
+ Hits        13516    13526   +10     
  Misses       1426     1426           

Impacted Files	Coverage Δ
Sources/ParseSwift/Objects/ParseUser+async.swift	94.23% <100.00%> (+0.12%)	⬆️
Sources/ParseSwift/Objects/ParseUser+combine.swift	95.86% <100.00%> (+0.14%)	⬆️

... and 2 files with indirect coverage changes

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