Fix an unintended change to Gemfile.lock (#909)

In #749 we
tried to bump the version of `jbuilder-schema`, but since it's a
dependency of `bullet_train-api` we need to leave it alone and let
it get upgraded naturally when we bump that gem.

Gemfile.lock

@@ -133,7 +133,7 @@ GEM
       bullet_train
       doorkeeper
       factory_bot
-      jbuilder-schema (>= 2.2.0)
+      jbuilder-schema (>= 2.0.0)
       pagy
       pagy_cursor
       rack-cors