fix: move test in the right folder

Author: cesco69

packages/pg/lib/pipeline-tests.js renamed to packages/pg/test/unit/client/pipeline-tests.js

@@ -1,6 +1,6 @@
 'use strict'
 
-const helper = require('../test-helper')
+const helper = require('./test-helper')
 const pg = helper.pg
 const assert = require('assert')