Patch: Fix active record insert values of type cast and serialize

Hello there. I found that Model#insert and Model#create were dealing with attribute conversion, and there were inconsistencies, and opened PR and tried to fix it. At present, this PR has been more than a year. I want to continue to advance it. What else do I need to do?

PR: Fix active record insert values of type cast and serialize by OuYangJinTing · Pull Request #48139 · rails/rails · GitHub