Fix Ruby 4.0 compatibility: replace deprecated CGI.parse

[jules-w2]

Summary

• Replace CGI.parse with URI.decode_www_form in ResumableSession
• Remove unused require 'cgi'

Context

Ruby 4.0 removed the cgi library from the standard library. Only cgi/escape remains available for basic escaping methods. This causes the following error when uploading videos: undefined method 'parse' for class CGI

Solution

Use URI.decode_www_form which is part of Ruby's core URI library and provides identical functionality. This is the recommended replacement per Ruby documentation.

Before:

CGI::parse(@uri.query).tap{|hash| hash.each{|k,v| hash[k] = v.first}}

After:

URI.decode_www_form(@uri.query || "").to_h

Testing
This change is backwards compatible with Ruby 3.x as URI.decode_www_form has been available since Ruby 1.9.2.

[kangkyu]

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