When using spring, it needs to be stopped before gdk update will work

From @engwan at #679 (comment 314532371)

PG::ObjectInUse: ERROR:  database "gitlabhq_test" is being accessed by other users
DETAIL:  There is 1 other session using the database.
/usr/local/opt/asdf/installs/ruby/2.6.5/bin/bundle:23:in `load'
/usr/local/opt/asdf/installs/ruby/2.6.5/bin/bundle:23:in `<main>'
Tasks: TOP => db:test:load => db:test:purge
(See full trace by running task with --trace)
make: *** [gitlab-update] Error 1

So I have to do bin/spring stop before gdk update