Upgrade CI to Ruby 3.0 release (#1296)

.circleci/config.yml

@@ -348,11 +348,11 @@ job_configuration:
   - &config-3_0
     <<: *filters_all_branches_and_tags
     ruby_version: '3.0'
-    image: marcotc/docker-library:ddtrace_rb_3.0.0-preview2
+    image: marcotc/docker-library:ddtrace_rb_3.0.0
   - &config-3_0-jit
     <<: *filters_all_branches_and_tags
     ruby_version: '3.0'
-    image: marcotc/docker-library:ddtrace_rb_3.0.0-preview2
+    image: marcotc/docker-library:ddtrace_rb_3.0.0
     jit: true
   # JRuby
   - &config-jruby-9_2

.circleci/images/primary/Dockerfile-3.0.0-preview2 → .circleci/images/primary/Dockerfile-3.0.0

@@ -1,5 +1,5 @@
-# https://hub.docker.com/layers/ruby/library/ruby/3.0.0-preview2/images/sha256-23faaa2700f13e4c11d632e2aac9ed39369c687e1e45dc468d501d60637adca5?context=explore
-FROM ruby@sha256:23faaa2700f13e4c11d632e2aac9ed39369c687e1e45dc468d501d60637adca5
+# https://hub.docker.com/layers/ruby/library/ruby/3.0.0/images/sha256-9719b7df964602b114a5e9319bd0a3ce2d4d44ccb7ea4d1702fa1ef9742a8f84
+FROM ruby@sha256:9719b7df964602b114a5e9319bd0a3ce2d4d44ccb7ea4d1702fa1ef9742a8f84
 
 # Make apt non-interactive
 RUN echo 'APT::Get::Assume-Yes "true";' > /etc/apt/apt.conf.d/90circleci \

Gemfile

@@ -2,10 +2,8 @@ source 'https://rubygems.org'
 
 gemspec
 
-# TODO: Use release gem when 'crack' releases version > 0.4.4, as we require
-# TODO https://github.com/jnunemaker/crack/pull/62 for Ruby 3.0 to work.
 if RUBY_VERSION >= '3.0.0'
-  gem 'crack', git: 'https://github.com/jnunemaker/crack.git', ref: 'c61172bf32e1769748fded156c2f2fc03dac69c1'
+  gem 'webrick', '>= 1.7.0' # No longer bundled by default since Ruby 3.0
 end
 
 # This file was generated by Appraisal

docker-compose.yml

@@ -249,7 +249,7 @@ services:
       - bundle-2.7:/usr/local/bundle
       - gemfiles-2.7:/app/gemfiles
   tracer-3.0:
-    image: marcotc/docker-library:ddtrace_rb_3.0.0-preview2
+    image: marcotc/docker-library:ddtrace_rb_3.0.0
     command: /bin/bash
     depends_on:
       - ddagent