Patch has broke for MSSQL adapter: selecting the same field twice returns an array

Steps to reproduce

The mssql knex adapter returns an array if the same field name is used more than once. Changes made in #181 have caused this to become an issue.

The following code will error:

const result = await app.service('uuids').patch(uid, { location:'Chicago' });

This line creates a duplicate uid field in the select statement:

feathers-knex/lib/index.js

Line 251 in f18dc99

query: _.extend({}, params.query, { $select: [ this.id ] })

Because we always append the id here:

feathers-knex/lib/index.js

Line 137 in f18dc99

q = filters.$select ? q.select(...filters.$select.concat(`${table}.${id}`))

This is the debug info from knex showing the double field:

{ method: 'select',
  options: {},
  timeout: false,
  cancelOnTimeout: false,
  bindings: [ 'FB9FFCB8-946B-45A3-BDAD-7311EB12182B' ],
  __knexQueryUid: 'a55481f2-dc42-4389-ae81-49619a327e3a',
  sql:
   'select [uid], [uuids].[uid] from [uuids] where (([uid] = ?))' }

The mssql adapter returns an array for uid for some unkown reason:

[ { uid:
     [ 'C958C0E3-3ACF-44E4-ADB3-8E9386A749BA',
       'C958C0E3-3ACF-44E4-ADB3-8E9386A749BA' ] } ]

So array is then passed into the update statement which causes the syntax error because its double wrapped in parentheses:

GeneralError: update [users] set [location] = @p0 where [id] in ((@p1, @p2));select @@rowcount - Incorrect syntax near ','.

Expected behavior

Tell us what should happen

patches without error

Actual behavior

Tell us what happens instead

syntax error

System configuration

Tell us about the applicable parts of your setup.

Module versions (especially the part that's not working):
"@feathersjs/feathers": "^3.3.1",
"feathers-knex": "^5.0.3",
"knex": "^0.14.6",
"mssql": "^4.1.0",

NodeJS version:
10.15.0

Closed via #189