nullable timestamptz support (`Date | null`)

[timvandam]

Describe the bug A clear and concise description of what the bug is.

Currently inserting/updating nullable timestamptz values in postgres don't work. Using variables of type Date | null causes error ESLint: Invalid Query: Unsupported union type(@ts-safeql/ check-sql)

To Reproduce Steps to reproduce the behavior:

Make a table with a nullable timestamptz column and try to insert a Date | null value

Expected behavior A clear and concise description of what you expected to happen.

It should work

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. iOS]
• PostgreSQL version [e.g. 13, 14]
• Version [e.g. 22]

Additional context Add any other context about the problem here.

I may have some time to try to fix this over the weekend