Add setRef to UpdateTableBuilder.

[igalklebanov]

Hey 👋

Currently, to refer to an existing column in query context, you either:

.set('target', (eb) => eb.ref('source'))

or:

.set((eb) => ({
  target: eb.ref('source'),
}))

Proposal:

Add setRef to UpdateQueryBuilder to allow:

.setRef('target', 'source')

and perhaps even:

.setRef({
  target: 'source',
})

...for use cases where all/most values are coming from referenced columns.

We should always look to provide ways not to use ExpressionBuilder if you're only referencing columns - callbacks are expensive at compile-time, and the query becomes less readable and harder to type.

[koskimas]

Makes sense!