Unable to paginate if `orderBy` on boolean type field is combined with pagination parameters
### Summary

If a table exposes a boolean type field for ordering
```sql
create table locations (
  id uuid default gen_random_uuid() primary key,
  name text not null unique,
  is_public boolean not null default true
);

create index idx_is_public on locations (is_public);

```

then we can execute a query using the `orderBy: IS_PUBLIC_ASC` successfuly, but if we combine the `orderBy` with a pagination paramater `after`, then the query fails with the following error:

```
Masked GraphQL error (hash: 'rxMy2h8uOCdYdguPLy4fcLXMWOg', id: '6ACWFQYMDJ') Error: f isn't a boolean; cowardly refusing to cast it to postgres
    at Object.toPg (/home/ruslik/.npm/_npx/e75fc4d1ace5dbd8/node_modules/@dataplan/pg/dist/codecs.js:536:23)
    at /home/ruslik/.npm/_npx/e75fc4d1ace5dbd8/node_modules/@dataplan/pg/dist/steps/pgSelect.js:650:59
    at Array.map (<anonymous>)
    at /home/ruslik/.npm/_npx/e75fc4d1ace5dbd8/node_modules/@dataplan/pg/dist/steps/pgSelect.js:648:40
    at Array.map (<anonymous>)
    at PgSelectStep.execute (/home/ruslik/.npm/_npx/e75fc4d1ace5dbd8/node_modules/@dataplan/pg/dist/steps/pgSelect.js:643:93)
    at executeOrStream (/home/ruslik/.npm/_npx/e75fc4d1ace5dbd8/node_modules/grafast/dist/engine/executeBucket.js:446:25)
    at executeStep (/home/ruslik/.npm/_npx/e75fc4d1ace5dbd8/node_modules/grafast/dist/engine/executeBucket.js:569:19)
    at nextPhase (/home/ruslik/.npm/_npx/e75fc4d1ace5dbd8/node_modules/grafast/dist/engine/executeBucket.js:109:31)
    at next (/home/ruslik/.npm/_npx/e75fc4d1ace5dbd8/node_modules/grafast/dist/engine/executeBucket.js:154:20) {
  path: [ 'allLocations', 'nodes' ],
  locations: [ { line: 3, column: 5 } ],
  extensions: [Object: null prototype] {}
}

```

### Steps to reproduce

https://github.com/ervasive/graphile-has-prev-page/tree/order-by-boolean-field
