run-migrations: include details from Postgres errors (getodk#1415)

Noticed while working on getodk#1363.

Currently, when a postgres error has additional details, `run-migrations.js` will swallow these details.

# Example

## migration

```js
module.exports = {
  down: () => {},
  up: db => db.raw(`
    INSERT INTO config (key) VALUES('a');
    INSERT INTO config (key) VALUES('a');
  `),
}
```

## logging - previous `master`

```
Error: INSERT INTO config (key) VALUES('a'); INSERT INTO config (key) VALUES('a') - duplicate key value violates unique constraint "config_pkey"
```

## logging - this commit

```
Error: INSERT INTO config (key) VALUES('a'); INSERT INTO config (key) VALUES('a') - duplicate key value violates unique constraint "config_pkey" (Key (key)=(a) already exists.)
```

Author: alxndrsn

lib/bin/run-migrations.js

@@ -13,7 +13,8 @@ const { withKnex, migrate } = require('../model/knex-migrator');
   try {
     await withKnex(require('config').get('default.database'))(migrate);
   } catch (err) {
-    console.error('Error:', err.message);
+    if (err.detail) console.error('Error:', err.message, `(${err.detail})`);
+    else            console.error('Error:', err.message); // eslint-disable-line no-multi-spaces
     process.exit(1);
   }
 })();