fix(gatsby): Package gatsby files properly

[AbhiPrasad]

See: #2706

As it stands gatsby-browser.js and gatsby-node.js aren't properly packaged into
the @sentry/gatsby distribution. Because of this Sentry.init() is never called
and the Sentry module is never bound to the window - loading the plugin is
effectively a nop. Unfortunately, the failure is silent.

Thanks to @klittlepage for reporting.

[getsentry-bot]

	Messages
📖	@sentry/browser bundle gzip'ed minified size: (ES5: 17.1387 kB) (ES6: 16.252 kB)
📖	✅ TSLint passed

Generated by 🚫 dangerJS against 87f46c1

[dcramer]

Oof, sorry about that. I think I had tested it in a diff structure then copied over the files once its as working.

[swannknani]

@dcramer, @AbhiPrasad The plugin doesn't look to be loaded properly because of missing gatsby-* files inside the npm folder.

version: "@sentry/gatsby": "5.19.1"

[webjay]

With 5.19.2 I get Can't resolve '@sentry/apm'.
Should I install that, or should you?

[AbhiPrasad]

@webjay Thank you for reporting, opened #2752 to make the change. For the time being, you can install the @sentry/apm package to get around any errors.