fix: resolve rubocop errors in instrumentation generators (#1333)

* fix: resolve Style/RedundantCurrentDirectoryInPath rubocop errors in instrumentation generator

* fix: resolve Layout/TrailingEmptyLines rubocop errors in instrumentation generator

Author: ymtdzzz

.instrumentation_generator/templates/Appraisals

@@ -13,4 +13,3 @@
 # appraise 'rack-2.0' do
 #   gem 'rack', '2.0.8'
 # end
-

.instrumentation_generator/templates/lib/entrypoint.rb

@@ -4,4 +4,4 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-require_relative './opentelemetry/instrumentation'
+require_relative 'opentelemetry/instrumentation'

.instrumentation_generator/templates/lib/instrumentation.rb.tt

@@ -16,4 +16,4 @@ module OpenTelemetry
   end
 end
 
-require_relative './instrumentation/<%= instrumentation_name %>'
+require_relative 'instrumentation/<%= instrumentation_name %>'

.instrumentation_generator/templates/lib/instrumentation/instrumentation_name.rb.tt

@@ -15,5 +15,5 @@ module OpenTelemetry
   end
 end
 
-require_relative './<%= instrumentation_name %>/instrumentation'
-require_relative './<%= instrumentation_name %>/version'
+require_relative '<%= instrumentation_name %>/instrumentation'
+require_relative '<%= instrumentation_name %>/version'