Prefer to use version constant for release management.

Gemfile

@@ -2,8 +2,8 @@
 
 source 'https://rubygems.org'
 
-gem 'git-version-bump', '~> 0.15'
-gem 'github-release', '~> 0.1'
+gemspec
+
 gem 'i18n', '~> 0.6', '>= 0.6.8'
 gem 'json', '~> 2.0'
 gem 'mime-types', '~> 3.0'
@@ -21,4 +21,7 @@ gem 'timecop', '~> 0.9'
 # Needed to have passing tests on Ruby 2.7, Ruby 3.0
 gem 'cgi', '>= 0.3.6' if RUBY_VERSION >= '2.7.0' && RUBY_VERSION <= '3.1.0'
 
-gemspec
+group :maintenance, optional: true do
+  gem "bake"
+  gem "bake-gem"
+end

Rakefile

@@ -1,14 +1,4 @@
 # frozen_string_literal: true
-# -*-ruby-*-
-exec(*(["bundle", "exec", $PROGRAM_NAME] + ARGV)) if ENV['BUNDLE_GEMFILE'].nil?
-
-begin
-	Bundler.setup(:default, :development)
-rescue Bundler::BundlerError => ex
-	$stderr.puts e.message
-	$stderr.puts "Run `bundle install` to install missing gems"
-	exit e.status_code
-end
 
 require 'rdoc/task'
 require 'rake/testtask'
@@ -33,12 +23,3 @@ RDoc::Task.new(:rdoc) do |rdoc|
   rdoc.rdoc_files.include('lib/rack/*.rb')
   rdoc.rdoc_files.include('lib/rack/*/*.rb')
 end
-
-
-# PACKAGING =================================================================
-
-Bundler::GemHelper.install_tasks
-
-task :release do
-	sh "git release"
-end

lib/rack/contrib/version.rb

@@ -0,0 +1,5 @@
+module Rack
+  module Contrib
+    VERSION = '2.3.0'
+  end
+end

rack-contrib.gemspec

@@ -1,18 +1,13 @@
 # frozen_string_literal: true
 
-begin
-  require 'git-version-bump'
-rescue LoadError
-  nil
-end
+require_relative 'lib/rack/contrib/version'
 
 Gem::Specification.new do |s|
   s.specification_version = 2 if s.respond_to? :specification_version=
   s.required_rubygems_version = Gem::Requirement.new(">= 0") if s.respond_to? :required_rubygems_version=
 
   s.name    = 'rack-contrib'
-  s.version = GVB.version rescue "0.0.0.1.ENOTAG"
-  s.date    = GVB.date    rescue Time.now.strftime("%F")
+  s.version = Rack::Contrib::VERSION
 
   s.licenses = ['MIT']