Stop modifying LOAD_PATH in specs

rspec automatically adds `spec/` to the load path, and adding `lib/` to
the load path does not serve a purpose from what I can see.

Author: ellnix

spec/spec_helper.rb

@@ -22,9 +22,6 @@
 require 'faker'
 require 'threads'
 
-$LOAD_PATH.unshift(File.dirname(__FILE__))
-$LOAD_PATH.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
-
 require 'meilisearch-rails'
 require 'rspec'
 require 'rails/all'