fix: move @electron/packager to dependencies

[Benricheson101]

Moves @electron/packager from devDependencies to dependencies so it is (recursively) installed by npm ci.

Otherwise this import throws a runtime error:

wdio-electron-service/src/application.ts

Line 9 in f6a5d6b

import { allOfficialArchsForPlatformAndVersion } from '@electron/packager';

[goosewobbler]

@Benricheson101 Good catch! I was able to reproduce the issue in wdio-electron-service-example. I'm wondering how this got past the E2Es - we need to ensure these issues will be caught before release - will look at this as part of #443.