Move the requires and constants for validation.

Should be where they are used really.

Author: hainesr

lib/cff.rb

@@ -18,7 +18,6 @@
 require 'json'
 require 'yaml'
 
-require 'json_schema'
 require 'language_list'
 
 # This library provides a Ruby interface to manipulate CITATION.cff files. The
@@ -29,7 +28,6 @@
 module CFF
   SCHEMA_PATH = ::File.join(__dir__, 'schema', '1.2.0.json') # :nodoc:
   SCHEMA_FILE = JSON.parse(::File.read(SCHEMA_PATH))         # :nodoc:
-  SCHEMA = JsonSchema.parse!(SCHEMA_FILE)                    # :nodoc:
 end
 
 require 'cff/version'

lib/cff/validatable.rb

@@ -14,12 +14,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+require 'json_schema'
+
 ##
 module CFF
 
   # Methods to validate CFF files/models against a formal schema.
   module Validatable
 
+    # :nodoc:
+    SCHEMA = JsonSchema.parse!(SCHEMA_FILE)
+
     # :call-seq:
     #   validate!(fail_fast: false)
     #