Remove unused files from package

[f440]

This pull request updates the *.gemspec file to optimize the gem package size and structure. The changes include:

• Modified files to exclude test files, Rakefile, and CI related files from the package.
• Removed the deprecated test_files specification as it is no longer recommended.

As a result of this change, the size of the unpacked package file will be reduced from 664KB to 60KB, achieving a reduction of approximately 90%.

Benefits:

• Shorter download times for users
• Reduced container sizes when the gem is included

References:

• Documentation about 'test_files' is confusing rubygems/guides#90
• Don't package test files with gem rubygems/bundler#3207

[knu]

Looks good. test_files should be obsolete by now.

[knu]

Oh, this broke test:

ruby-unf/Rakefile

Line 9 in 04d6c8a

test.test_files = gemspec.test_files

[f440]

Ah, I missed that. I just saw that you've already fixed the issue in the recent commit. Thanks so much for picking up on that so quickly! Sorry for any trouble I caused.