Partition commands not supported by parser

[qoelet]

When a migration includes partition maintenance commands, such as

ALTER TABLE measurement ATTACH PARTITION measurement_y2008m02
    FOR VALUES FROM ('2008-02-01') TO ('2008-03-01' );
ALTER TABLE measurement DETACH PARTITION measurement_y2006m02;

running Squawk results in the following error

note: Squawk schema failed to parse Postgres response. This indicates a bug with Squawk. Please report this error to https://github.com/sbdchd/squawk. Schema error: unknown variant `PartitionCmd`, expected one of `TypeCast`, `FuncCall`, `Constraint`, `ColumnDef`, `A_Const`, `ReplicaIdentityStmt`, `SQLValueFunction` at line 1 column 252
  help: Modify your Postgres statement to use valid syntax.

Besides fixing this, I suppose we would ideally want new rules for Squawk that would warn users about ACCESS EXCLUSIVE locks on the parent table and suggest

1. Use DETACH PARTITION ... CONCURRENTLY
2. Add a CHECK constraint before ATTACH PARTITION commands

Both of the above would drop the lock requirement to SHARE UPDATE EXCLUSIVE, which is an improvement. Thoughts?