Fix YAML load for ruby 3.1.

See ruby/psych#487 for more information.

Author: wpolicarpo

test/cases/coerced_tests.rb

@@ -1486,7 +1486,8 @@ class YamlSerializationTest < ActiveRecord::TestCase
   coerce_tests! :test_types_of_virtual_columns_are_not_changed_on_round_trip
   def test_types_of_virtual_columns_are_not_changed_on_round_trip_coerced
     author = Author.select("authors.*, 5 as posts_count").first
-    dumped = YAML.load(YAML.dump(author))
+    dumped_author = YAML.dump(author)
+    dumped = YAML.respond_to?(:unsafe_load) ? YAML.unsafe_load(dumped_author) : YAML.load(dumped_author)
     assert_equal 5, author.posts_count
     assert_equal 5, dumped.posts_count
   end

test/cases/rake_test_sqlserver.rb

@@ -176,7 +176,8 @@ class SQLServerRakeSchemaCacheDumpLoadTest < SQLServerRakeTest
   it "dumps schema cache with SQL Server metadata" do
     quietly { db_tasks.dump_schema_cache connection, filename }
 
-    schema_cache = YAML.load(File.read(filename))
+    filedata = File.read(filename)
+    schema_cache = YAML.respond_to?(:unsafe_load) ? YAML.unsafe_load(filedata) : YAML.load(filedata)
 
     col_id, col_name = connection.schema_cache.columns("users")