gitignore semconv repo clone; rake improvements

* Move to a tmp/ dir and ignore that.

* Update the git commands to be able to reuse one directory for
  the repo working copy, just update what's needed for a different
  tag between iterations. (Generally only an improvement for dev envs.)

* Use sh() for shell commands so that tasks fail if their commands fail.

* Appease Rubocop.

semantic_conventions/.gitignore

@@ -0,0 +1 @@
+tmp/

semantic_conventions/Rakefile

@@ -32,22 +32,22 @@ end
 
 SPEC_VERSION = '1.25.0'
 GENERATOR_VERSION = '0.24.0'
-semconv_source_dir = Pathname.new("./tmpsemconvrepo_v#{SPEC_VERSION}")
+semconv_source_dir = Pathname.new('./tmp/semconvrepo')
 conventions_output_dir = Pathname.new('./lib/opentelemetry/semantic_conventions')
 candidates_output_dir = Pathname.new('./lib/opentelemetry/semantic_candidates')
 
-EXCLUDED_ATTRIBUTES = %w[]
+EXCLUDED_ATTRIBUTES = %w[].freeze
 
 task generate: %i[update_gem_version generate_stable_attributes generate_candidate_attributes]
 
 directory semconv_source_dir do
-  `git clone --depth=1 --branch v#{SPEC_VERSION} https://github.com/open-telemetry/semantic-conventions.git #{semconv_source_dir}`
+  sh "git clone --tags --depth=1 --branch v#{SPEC_VERSION} https://github.com/open-telemetry/semantic-conventions.git #{semconv_source_dir}"
 end
 
 task check_out_semconv_version: [semconv_source_dir] do
   Dir.chdir(semconv_source_dir) do
-    `git fetch`
-    `git checkout "v#{SPEC_VERSION}"`
+    sh "git fetch --depth 1 origin tag v#{SPEC_VERSION}"
+    sh "git checkout 'v#{SPEC_VERSION}'"
   end
 end
 
@@ -88,10 +88,10 @@ def semconvgen(semconv_source, output_root:, kind:, selector:)
   ]
 
   puts "Running: #{cmd.join(' ')}"
-  `#{cmd.join(' ')}`
+  sh cmd.join(' ')
 end
 
 task :update_gem_version do
-  `sed -i.bak "s/VERSION = '.*'/VERSION = '#{SPEC_VERSION}'/g" lib/opentelemetry/semantic_conventions/version.rb`
-  `rm lib/opentelemetry/semantic_conventions/version.rb.bak`
+  sh %(sed -i.bak "s/VERSION = '.*'/VERSION = '#{SPEC_VERSION}'/g" lib/opentelemetry/semantic_conventions/version.rb)
+  sh 'rm lib/opentelemetry/semantic_conventions/version.rb.bak'
 end

semantic_conventions/test/opentelemetry/semantic_conventions/attributes_test.rb

@@ -19,7 +19,7 @@
           .const_get(root_namespace)
           .constants
           .each do |stable_const|
-            it "#{stable_const}" do
+            it stable_const.to_s do
               candidate_namespace = OpenTelemetry::SemanticCandidates.const_get(root_namespace)
               assert candidate_namespace.constants.include?(stable_const), "Missing stable constant in candidates: #{stable_const}"
             end

semantic_conventions/test/test_helper.rb

@@ -13,4 +13,4 @@
 require 'minitest/autorun'
 require 'pry'
 
-Dir[File.join(File.dirname(__FILE__), '..', 'lib', 'opentelemetry', '**', '*.rb')].sort.each { |file| require file }
+Dir[File.join(File.dirname(__FILE__), '..', 'lib', 'opentelemetry', '**', '*.rb')].each { |file| require file }