fix: remove psych pin, re-record cassettes and fix tests

easypost.gemspec

@@ -24,7 +24,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'brakeman', '~> 5.4'
   spec.add_development_dependency 'faraday', '~> 2.7.5' # used for integration tests
   spec.add_development_dependency 'pry', '~> 0.14'
-  spec.add_development_dependency 'psych', '~> 5.1'
   spec.add_development_dependency 'rake', '~> 13.0'
   spec.add_development_dependency 'rdoc', '~> 6.5'
   spec.add_development_dependency 'rspec', '~> 3.12'

spec/beta_rate_spec.rb

@@ -18,7 +18,7 @@
 
         lowest_stateless_rate = EasyPost::Util.get_lowest_stateless_rate(stateless_rates)
 
-        expect(lowest_stateless_rate.service).to match('First')
+        expect(lowest_stateless_rate.service).to match('GroundAdvantage')
 
         expect {
           EasyPost::Util.get_lowest_stateless_rate(stateless_rates, ['invalid_carrier'])

spec/beta_referral_spec.rb

@@ -2,14 +2,11 @@
 
 require 'spec_helper'
 
-REFERRAL_CUSTOMER_PROD_API_KEY = ENV['REFERRAL_CUSTOMER_PROD_API_KEY'] || '123'
-
 describe EasyPost::Services::BetaReferralCustomer do
   let(:client) { EasyPost::Client.new(api_key: ENV['PARTNER_USER_PROD_API_KEY'] || '123') }
 
   describe '.add_payment_method' do
     it 'adds a Stripe card or bank account to a referral customer account' do
-      # This test requires a referral customer's production API key via REFERRAL_CUSTOMER_PROD_API_KEY.
       expect {
         client.beta_referral_customer.add_payment_method(
           'cus_123',
@@ -21,7 +18,6 @@
 
   describe '.refund_by_amount' do
     it 'refunds a referral user by a specific amount' do
-      # This test requires a referral customer's production API key via REFERRAL_CUSTOMER_PROD_API_KEY.
       expect {
         client.beta_referral_customer.refund_by_amount(
           2000,
@@ -34,7 +30,6 @@
 
   describe '.refund_by_payment_log' do
     it 'refunds a referral user by a specific payment log entry' do
-      # This test requires a referral customer's production API key via REFERRAL_CUSTOMER_PROD_API_KEY.
       expect {
         client.beta_referral_customer.refund_by_payment_log(
           'paylog_123',