Migrations: Serialized Alembic Migration Counter Conflict

[Prajna1999]

Describe the current behavior
Serialized alembic migration counter creates conflicts if two people are working on diverging branches. It requires extra co-ordination efforts.

Describe the enhancement you'd like
Revert back to hash based migration so that we are not stepping on other branch's work.

Why is this enhancement needed?
Avoid downstream merge conflicts.

Additional context
Screenshot showing conflict

[Prajna1999]

looping in @kartpop