CreateTaggableTable gets republished each time a migration from a different library is published

[Scaenicus]

Reproduce

• Run php artisan vendor:publish --tag=migrations thrice
  • class CreateTaggableTable gets created 3 times (each with a new timestamp)
  • However even the first time would be unnecessary since I still can find the previous version's 0000_00_00_000000_create_taggable_table in the migrations.
• Also tested after composer dumpautoload in between, but still the migrations get republished each time.

[cviebrock]

Yeah, I made some changes to the migration code. In short, if you are just upgrading from an old version, and already have the required tables/migrations, you can skip the artisan vendor:publish step. That would only apply to new installs.