[WIP] Rename Singular Attributes

[dehume]

Fixes #391

Implement two attribute name changes for 2 schema.TypeList that are singular that should be plural. Including StateUpgraders to and make this as easy as possible for existing resources.

Resource	Old Attribute	New Attribute
source kafka	start_offset	start_offsets
source postgres	schema	schemas

[dehume]

Still working on this. Still working on finding better examples of doing the migration tests.

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✅ dehume
❌ Dennis Hume

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