fix: require csv for ruby-3.4 compatibility (#1560)

Loading exporter/otlp, exporter/otlp/http or exporter/zipkin on
ruby-3.3 now prints a warning:

    .../lib/opentelemetry/exporter/otlp/exporter.rb:10: warning: csv
    was loaded from the standard library, but will no longer be part
    of the default gems since Ruby 3.4.0. Add csv to your Gemfile or
    gemspec. Also contact author of opentelemetry-exporter-otlp-0.26.1
    to add csv into its gemspec.

exporter/otlp and exporter/otlp/http do not actually depend on csv,
though. Therefore this was fixed by removing the require statement.

exporter/zipkin, on the other hand, does depend on csv. So an explicit
dependency was added to the csv gem at version '~> 3.1' (ruby-3.0
bundles csv at 3.1.9).

Co-authored-by: Matthew Wear <[email protected]>

exporter/otlp-http/lib/opentelemetry/exporter/otlp/http/trace_exporter.rb

@@ -8,7 +8,6 @@
 require 'opentelemetry/exporter/otlp/common'
 require 'opentelemetry/sdk'
 require 'net/http'
-require 'csv'
 require 'zlib'
 
 require 'google/rpc/status_pb'

exporter/otlp/lib/opentelemetry/exporter/otlp/exporter.rb

@@ -7,7 +7,6 @@
 require 'opentelemetry/common'
 require 'opentelemetry/sdk'
 require 'net/http'
-require 'csv'
 require 'zlib'
 
 require 'google/rpc/status_pb'

exporter/zipkin/opentelemetry-exporter-zipkin.gemspec

@@ -26,6 +26,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
   spec.required_ruby_version = '>= 3.0'
 
+  spec.add_dependency 'csv', '~> 3.1'
   spec.add_dependency 'opentelemetry-api', '~> 1.1'
   spec.add_dependency 'opentelemetry-common', '~> 0.20'
   spec.add_dependency 'opentelemetry-sdk', '~> 1.2'