[Feature Request][Go SDK]: Generate Postgres compatible placeholders for pgx driver

[johannaojeling]

What would you like to happen?

If using the pgx driver for a Postgres database in databaseio.Write, a prepared statement with default placeholders like "(?,?,?),(?,?,?)" is generated for the values to insert. Include "pgx" in the Postgres value template generation case, so that the value template follows the pattern "($1,$2,$3),($4,$5,$6)" instead.

Issue Priority

Priority: 2 (default / most feature requests should be filed as P2)

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[johannaojeling]

.take-issue