Add support for Sentry release ENV

[alekseyp]

Add support to pass Sentry release as ENV variable

[bennothommo]

@alekseyp is the SENTRY_RELEASE environment variable always specified? We may have to comment it out and leave it as an example, like the original comment.

[alekseyp]

@alekseyp is the SENTRY_RELEASE environment variable always specified? We may have to comment it out and leave it as an example, like the original comment.

It's exactly the same as any other env set in this config. All of them are not always specified.

Inside sentry/sentry-laravel it's then simply checks if it's set or not.

For example:

                        if (!empty($this->release) && !$event->getRelease()) {
                            $event->setRelease($this->release);
                        }