Online schema changes for cloudsql DB

I'm new to cloudsql for mysql. I have a table with trigger. I need to do some ddl changes on that table. However, I can't take any downtime. **What I have tried so far:** I tried with pt-online-schema-change. Because, it work for our local databases. However, in case of managed cloudsql - it wasn't working. Opened an issue with Percona(PT-1964). Next, I checked for gh-ost. However, as per their documentation(https://github.com/github/gh-ost/blob/master/doc/requirements-and-limitations.md) -it doesn't support any table with trigger. Making changes with shared lock option isn't available for me - because we have a replica too. Does anyone knows any other method/suggeation to make ddl changes online for cloudsql for mysql. Thanks in advance!