fix: correctly handle integer -> bigint conversion

[levkk]

Instead of appending ALTER TABLE ... ALTER COLUMN ... TYPE BIGINT, we modify CREATE TABLE statement in-place, changing the column type from integer to bigint, iff the column is part of a primary key constraint.

[codecov]

Codecov Report

❌ Patch coverage is 92.66409% with 19 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
pgdog/src/backend/schema/sync/pg_dump.rs	92.66%	19 Missing ⚠️

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