Use require_relative instead of $LOAD_PATH in gemspec

[ericproulx]

Use require_relative instead of $LOAD_PATH in gemspec

Description

This PR simplifies the gemspec by replacing the $LOAD_PATH manipulation with require_relative, which is more idiomatic and cleaner for Ruby gems.

Changes

• Removed $LOAD_PATH.unshift File.expand_path('lib', __dir__)
• Replaced require 'grape/version' with require_relative 'lib/grape/version'

Benefits

1. Simplicity: require_relative is more straightforward and doesn't mutate global state
2. Idiomatic: Follows modern Ruby best practices for gemspecs
3. Safety: Avoids potential pollution of $LOAD_PATH that could affect other gems

Context

This follows a modern Ruby convention where require_relative is preferred over manipulating $LOAD_PATH in gemspecs. The previous approach was added in #1758 to fix issues with Grape::VERSION potentially referencing system-wide installed gem versions, but require_relative provides the same isolation without global state mutation.

Testing

• ✅ All existing tests pass
• ✅ Gem builds successfully
• ✅ Version constant loads correctly

[grape-bot]

	1 Message
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