Can't autosync Gemfile_next.lock when using `bundle lock`

[Edouard-chin]

If the Gemfile.lock got updated by someone running bundle lock --update my_gem, bootboot isn't able to update the Gemfile_next.lock because the Bundler after-install-all hook is not triggered by Bundler.

Second problem is that bundle lock doesn't install any gems nor plugins, if a dev doesn't have the bootboot plugin already installed (through a prior bundle install call for example), bootboot won't even get installed.

First issue sounds like something we can fix upstream by triggering a more generic hook like after-gemfile-lock-update whenever a bundler command updates the lockfile.

I'm not too sure what to do about the second issue yet