Update instrumentation generator to use inline bundler (#87)

update instrumentation generator to use inline bundler

Author: plantfansam

.instrumentation_generator/instrumentation_generator.rb

@@ -4,9 +4,15 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-require_relative '../api/lib/opentelemetry/version'
+require 'bundler/inline'
+
+gemfile do
+  source 'https://rubygems.org'
+  gem 'opentelemetry-api'
+  gem 'thor'
+end
+
 require_relative '../instrumentation/base/lib/opentelemetry/instrumentation/version'
-require 'thor'
 
 class InstrumentationGenerator < Thor::Group
   include Thor::Actions

.instrumentation_generator/templates/gemspec.tt

@@ -23,7 +23,7 @@ Gem::Specification.new do |spec|
                ::Dir.glob('*.md') +
                ['LICENSE', '.yardopts']
   spec.require_paths = ['lib']
-  spec.required_ruby_version = '>= 2.6.0'
+  spec.required_ruby_version = '>= 2.7.6'
 
   spec.add_dependency 'opentelemetry-api', '~> <%= opentelemetry_version %>'
   spec.add_dependency 'opentelemetry-instrumentation-base', '~> <%= instrumentation_base_version %>'