V3 backport: Fixes QueryInterface#changeColumn for enums

[seshness]

Pull Request check-list

• Does npm run test or npm run test-DIALECT pass with this change (including linting)?
• Does your issue contain a link to existing issue (Closes #[issue]) or a description of the issue you are solving?
• Have you added new tests to prevent regressions?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• Have you added an entry under Future in the changelog?

Description of change

Previous changes to support schemas in QueryInterface generated invalid Postgres SQL when attempting to change a column to an enum value.

Instead of generating

ALTER TABLE "myTable" ALTER COLUMN "col_1" TYPE "public"."enum_myTable_col_1" USING ("col_1"::"public.enum_myTable_col_1");

with this change we will now generate

ALTER TABLE "myTable" ALTER COLUMN "col_1" TYPE "public"."enum_myTable_col_1" USING ("col_1"::"public"."enum_myTable_col_1");

[mention-bot]

@seshness, thanks for your PR! By analyzing the history of the files in this pull request, we identified @overlookmotel, @jonathana and @durango to be potential reviewers.

[codecov-io]

Codecov Report

Merging #7456 into v3 will increase coverage by 0.04%.
The diff coverage is 100%.

[sushantdhiman]

@seshness Needs a changelog entry

[FIXED] `changeColumn` generates incorrect query with ENUM type [#7456](https://github.com/sequelize/sequelize/pull/7456)