Adjust to upcoming Julia 1.12 change in implicit world age increment

In 1.12, we'll be cleaning up and making consistent when world age
increment happens. This package is currently relying on implicit world
age increments that may go away in 1.12. See JuliaLang/julia#56509.
This PR adds appropriate annotations that the world age increment
is required because the `_generate_*` invocations in the macro read
the result of the previous eval. This PR strictly retains existing
behavior. A potentially better solution may be to `invokelatest`
the `_generate_*` functions, which would also allow this code
to work at non-toplevel (which may nor may not be desirable).

src/schemas.jl

@@ -865,6 +865,8 @@ macro version(record_type, declared_fields_block=nothing)
     declared_field_names_types = Expr(:tuple, Expr(:parameters, (Expr(:kw, f.name, esc(f.type)) for f in declared_field_infos)...))
     constraints = [Base.Meta.quot(ex) for ex in declared_constraint_statements]
 
+    latestworld = isdefined(Core, :var"@latestworld") ? :(@Core.latestworld) : nothing
+
     return quote
         if !isdefined((@__MODULE__), :__legolas_schema_name_from_prefix__)
             throw(SchemaVersionDeclarationError("no prior `@schema` declaration found in current module"))
@@ -890,7 +892,9 @@ macro version(record_type, declared_fields_block=nothing)
             else
                 Base.@__doc__($(Base.Meta.quot(record_type)))
                 $(esc(:eval))($Legolas._generate_schema_version_definitions(schema_version, parent, $declared_field_names_types, schema_version_declaration))
+                $latestworld
                 $(esc(:eval))($Legolas._generate_validation_definitions(schema_version))
+                $latestworld
                 $(esc(:eval))($Legolas._generate_record_type_definitions(schema_version, $(Base.Meta.quot(record_type)), [$(constraints...)]))
             end
         end